ltsmin: implement a two-step loading

* spot/ltsmin/ltsmin.cc, spot/ltsmin/ltsmin.hh: Split load_ltsmin() into
ltsmin_model::load() and ltsmin_model::kripke().  Report errors using
exceptions instead of on std::cerr.
* python/spot/ltsmin.i: Deal with exceptions.
* tests/ltsmin/modelcheck.cc, tests/python/ltsmin.ipynb: Adjust.

NEWS

@@ -5,6 +5,16 @@ New in spot 1.99.7a (not yet released)
   * Building products with different dictionaries now raise an
     exception instead of using an assertion that could be disabled.
 
+  * The load_ltsmin() function has been split in two.  Now you should
+    first call ltsmin_model::load(filename) to create an ltlmin_model,
+    and then call the ltsmin_model::kripke(...) method to create an
+    automaton that can be iterated on the fly.
+
+  Python:
+
+  * The ltsmin interface has been binded in Python.  See
+    https://spot.lrde.epita.fr/ipynb/ltsmin.html for a short example.
+
   Documentation:
 
   * There is a new page giving informal illustrations (and extra

python/spot/ltsmin.i

@@ -47,20 +47,36 @@ using namespace spot;
 %import(module="spot.impl") <spot/kripke/fairkripke.hh>
 %import(module="spot.impl") <spot/kripke/kripke.hh>
 
+%exception {
+  try {
+    $action
+  }
+  catch (const std::runtime_error& e)
+  {
+    SWIG_exception(SWIG_RuntimeError, e.what());
+  }
+}
+
 namespace std {
   %template(atomic_prop_set) set<spot::formula>;
 }
 
+%rename(model) spot::ltsmin_model;
+%rename(kripke_raw) spot::ltsmin_model::kripke;
 %include <spot/ltsmin/ltsmin.hh>
 
 %pythoncode %{
 import spot
 
-def load(filename, ap_set, dict=spot._bdd_dict,
+def load(filename):
-         dead=spot.formula_ap('dead'),
+  return model.load(filename)
-         compress=2, debug=False):
+
+def _kripke(self, ap_set, dict=spot._bdd_dict,
+            dead=spot.formula_ap('dead'),
+            compress=2):
   s = spot.atomic_prop_set()
   for ap in ap_set:
     s.insert(spot.formula_ap(ap))
-  return load_ltsmin(filename, dict, s, dead, compress, debug)
+  return self.kripke_raw(s, dict, dead, compress)
+model.kripke = _kripke
 %}

spot/ltsmin/ltsmin.cc

@@ -1,5 +1,5 @@
 // -*- coding: utf-8 -*-
-// Copyright (C) 2011, 2012, 2014, 2015 Laboratoire de Recherche et
+// Copyright (C) 2011, 2012, 2014, 2015, 2016 Laboratoire de Recherche et
 // Développement de l'Epita (LRDE)
 //
 // This file is part of Spot, a model checking library.
@@ -53,21 +53,33 @@ namespace spot
     typedef void (*TransitionCB)(void *ctx,
 				 transition_info_t *transition_info,
 				 int *dst);
+  }
 
-    struct spins_interface
+  struct spins_interface
+  {
+    lt_dlhandle handle;	// handle to the dynamic library
+    void (*get_initial_state)(void *to);
+    int (*have_property)();
+    int (*get_successors)(void* m, int *in, TransitionCB, void *arg);
+    int (*get_state_size)();
+    const char* (*get_state_variable_name)(int var);
+    int (*get_state_variable_type)(int var);
+    int (*get_type_count)();
+    const char* (*get_type_name)(int type);
+    int (*get_type_value_count)(int type);
+    const char* (*get_type_value_name)(int type, int value);
+
+    ~spins_interface()
     {
-      lt_dlhandle handle;	// handle to the dynamic library
+      if (handle)
-      void (*get_initial_state)(void *to);
+	lt_dlclose(handle);
-      int (*have_property)();
+      lt_dlexit();
-      int (*get_successors)(void* m, int *in, TransitionCB, void *arg);
+    }
-      int (*get_state_size)();
+  };
-      const char* (*get_state_variable_name)(int var);
+
-      int (*get_state_variable_type)(int var);
+  namespace
-      int (*get_type_count)();
+  {
-      const char* (*get_type_name)(int type);
+    typedef std::shared_ptr<const spins_interface> spins_interface_ptr;
-      int (*get_type_value_count)(int type);
-      const char* (*get_type_value_name)(int type, int value);
-    };
 
     ////////////////////////////////////////////////////////////////////////
     // STATE
@@ -322,14 +334,15 @@ namespace spot
     };
 
 
-    int
+    void
     convert_aps(const atomic_prop_set* aps,
-		const spins_interface* d,
+		spins_interface_ptr d,
 		bdd_dict_ptr dict,
 		formula dead,
 		prop_set& out)
     {
       int errors = 0;
+      std::ostringstream err;
 
       int state_size = d->get_state_size();
       typedef std::map<std::string, var_info> val_map_t;
@@ -367,8 +380,7 @@ namespace spot
 	    ++s;
 	  if (!*s)
 	    {
-	      std::cerr << "Proposition `" << str
+	      err << "Proposition `" << str << "' cannot be parsed.\n";
-			<< "' cannot be parsed." << std::endl;
 	      ++errors;
 	      continue;
 	    }
@@ -393,8 +405,7 @@ namespace spot
 
 	  if (name == name_p)
 	    {
-	      std::cerr << "Proposition `" << str
+	      err << "Proposition `" << str << "' cannot be parsed.\n";
-			<< "' cannot be parsed." << std::endl;
 	      free(name);
 	      ++errors;
 	      continue;
@@ -415,9 +426,9 @@ namespace spot
 
 	      if (ni == val_map.end())
 		{
-		  std::cerr << "No variable `" << name
+		  err << "No variable `" << name
-			    << "' found in model (for proposition `"
+		      << "' found in model (for proposition `"
-			    << str << "')." << std::endl;
+		      << str << "').\n";
 		  free(name);
 		  ++errors;
 		  continue;
@@ -429,14 +440,12 @@ namespace spot
 	      enum_map_t::const_iterator ei = enum_map[type_num].find(lastdot);
 	      if (ei == enum_map[type_num].end())
 		{
-		  std::cerr << "No state `" << lastdot
+		  err << "No state `" << lastdot << "' known for variable `"
-			    << "' known for variable `"
+		      << name << "'.\n";
-			    << name << "'." << std::endl;
+		  err << "Possible states are:";
-		  std::cerr << "Possible states are:";
+		  for (auto& ej: enum_map[type_num])
-		  for (ei = enum_map[type_num].begin();
+		    err << ' ' << ej.first;
-		       ei != enum_map[type_num].end(); ++ei)
+		  err << '\n';
-		    std::cerr << ' ' << ei->first;
-		  std::cerr << '\n';
 
 		  free(name);
 		  ++errors;
@@ -446,16 +455,16 @@ namespace spot
 	      // At this point, *s should be 0.
 	      if (*s)
 		{
-		  std::cerr << "Trailing garbage `" << s
+		  err << "Trailing garbage `" << s
-			    << "' at end of proposition `"
+		      << "' at end of proposition `"
-			    << str << "'." << std::endl;
+		      << str << "'.\n";
 		  free(name);
 		  ++errors;
 		  continue;
 		}
 
 	      // Record that X.Y must be equal to Z.
-	      int v = dict->register_proposition(*ap, d);
+	      int v = dict->register_proposition(*ap, d.get());
 	      one_prop p = { ni->second.num, OP_EQ, ei->second, v };
 	      out.push_back(p);
 	      free(name);
@@ -515,9 +524,9 @@ namespace spot
 	      break;
 	    default:
 	    report_error:
-	      std::cerr << "Unexpected `" << s
+	      err << "Unexpected `" << s
-			<< "' while parsing atomic proposition `" << str
+		  << "' while parsing atomic proposition `" << str
-			<< "'." << std::endl;
+		  << "'.\n";
 	      ++errors;
 	      free(name);
 	      continue;
@@ -534,8 +543,7 @@ namespace spot
 	      val = strtol(s, &s_end, 10);
 	      if (s == s_end)
 		{
-		  std::cerr << "Failed to parse `" << s
+		  err << "Failed to parse `" << s << "' as an integer.\n";
-			    << "' as an integer." << std::endl;
 		  ++errors;
 		  free(name);
 		  continue;
@@ -555,14 +563,13 @@ namespace spot
 	      enum_map_t::const_iterator ei = enum_map[type_num].find(st);
 	      if (ei == enum_map[type_num].end())
 		{
-		  std::cerr << "No state `" << st
+		  err << "No state `" << st << "' known for variable `"
-			    << "' known for variable `"
+		      << name << "'.\n";
-			    << name << "'." << std::endl;
+		  err << "Possible states are:";
-		  std::cerr << "Possible states are:";
 		  for (ei = enum_map[type_num].begin();
 		       ei != enum_map[type_num].end(); ++ei)
-		    std::cerr << ' ' << ei->first;
+		    err << ' ' << ei->first;
-		  std::cerr << '\n';
+		  err << '\n';
 
 		  free(name);
 		  ++errors;
@@ -578,11 +585,11 @@ namespace spot
 	    ++s;
 	  if (*s)
 	    {
-	      std::cerr << "Unexpected `" << s
+	      err << "Unexpected `" << s
-			<< "' while parsing atomic proposition `" << str
+		  << "' while parsing atomic proposition `" << str
-			<< "'." << std::endl;
+		  << "'.\n";
-		  ++errors;
+	      ++errors;
-		  continue;
+	      continue;
 	    }
 
 
@@ -591,7 +598,8 @@ namespace spot
 	  out.push_back(p);
 	}
 
-      return errors;
+      if (errors)
+	throw std::runtime_error(err.str());
     }
 
     ////////////////////////////////////////////////////////////////////////
@@ -601,7 +609,7 @@ namespace spot
     {
     public:
 
-      spins_kripke(const spins_interface* d, const bdd_dict_ptr& dict,
+      spins_kripke(spins_interface_ptr d, const bdd_dict_ptr& dict,
 		   const spot::prop_set* ps, formula dead,
 		   int compress)
 	: kripke(dict),
@@ -679,13 +687,9 @@ namespace spot
 	    delete[] uncompressed_;
 	    delete[] compressed_;
 	  }
-	lt_dlclose(d_->handle);
+	dict_->unregister_all_my_variables(d_.get());
 
-	dict_->unregister_all_my_variables(d_);
-
-	delete d_;
 	delete ps_;
-	lt_dlexit();
 
 	if (state_condition_last_state_)
 	  state_condition_last_state_->destroy();
@@ -918,7 +922,7 @@ namespace spot
       }
 
     private:
-      const spins_interface* d_;
+      spins_interface_ptr d_;
       int state_size_;
       bdd_dict_ptr dict_;
       const char** vname_;
@@ -950,8 +954,8 @@ namespace spot
 
     // Call spins to compile "foo.prom" as "foo.prom.spins" if the latter
     // does not exist already or is older.
-    static bool
+    static void
-    compile_model(std::string& filename, std::string& ext, bool verbose)
+    compile_model(std::string& filename, std::string& ext)
     {
       std::string command;
       std::string compiled_ext;
@@ -968,22 +972,14 @@ namespace spot
 	}
       else
 	{
-	  if (verbose)
+	  throw std::runtime_error(std::string("Unknown extension '")
-	    std::cerr << "Unknown extension `" << ext
+				   + ext + "'.  Use '.prom', '.pm', '.pml', "
-		      << ("'.  Use `.prom', `.pm', `.pml', `.dve', `.dve2C' or"
+				   "'.dve', '.dve2C', or '.prom.spins'.");
-			  "`.prom.spins'.") << std::endl;
-	  return false;
 	}
 
       struct stat s;
       if (stat(filename.c_str(), &s) != 0)
-	{
+	throw std::runtime_error(std::string("Cannot open ") + filename);
-	  if (verbose)
-	    {
-	      std::cerr << "Cannot open " << filename << std::endl;
-	      return true;
-	    }
-	}
 
       std::string old = filename;
       filename += compiled_ext;
@@ -998,26 +994,19 @@ namespace spot
       if (stat(filename.c_str(), &d) == 0)
 	if (s.st_mtime < d.st_mtime)
 	  // The .spins or .dve2C is up-to-date, no need to recompile it.
-	  return false;
+	  return;
 
       int res = system(command.c_str());
       if (res)
-	{
+	throw std::runtime_error(std::string("Execution of '")
-	  if (verbose)
+				 + command.c_str() + "' returned exit code "
-	    std::cerr << "Execution of `" << command.c_str()
+				 + std::to_string(WEXITSTATUS(res)));
-		      << "' returned exit code " << WEXITSTATUS(res)
-		      << ".\n";
-	  return true;
-	}
-      return false;
     }
 
   }
 
-  kripke_ptr
+  ltsmin_model
-  load_ltsmin(const std::string& file_arg, const bdd_dict_ptr& dict,
+  ltsmin_model::load(const std::string& file_arg)
-	      const atomic_prop_set* to_observe,
-	      const formula dead, int compress, bool verbose)
   {
     std::string file;
     if (file_arg.find_first_of("/\\") != std::string::npos)
@@ -1027,33 +1016,20 @@ namespace spot
 
     std::string ext = file.substr(file.find_last_of("."));
     if (ext != ".spins" && ext != ".dve2C")
-      {
+      compile_model(file, ext);
-        if (compile_model(file, ext, verbose))
-          {
-            if (verbose)
-              std::cerr << "Failed to compile `" << file_arg
-              << "'." << std::endl;
-            return nullptr;
-          }
-      }
 
     if (lt_dlinit())
-      {
+      throw std::runtime_error("Failed to initialize libltldl.");
-	if (verbose)
-	  std::cerr << "Failed to initialize libltdl." << std::endl;
-	return nullptr;
-      }
 
     lt_dlhandle h = lt_dlopen(file.c_str());
     if (!h)
       {
-	if (verbose)
-	  std::cerr << "Failed to load `" << file << "'." << std::endl;
 	lt_dlexit();
-	return nullptr;
+	throw std::runtime_error(std::string("Failed to load '")
+				 + file + "'.");
       }
 
-    spins_interface* d = new spins_interface;
+    auto d = std::make_shared<spins_interface>();
     d->handle = h;
 
     // SpinS interface.
@@ -1112,36 +1088,38 @@ namespace spot
 	  && d->get_type_name
 	  && d->get_type_value_count
 	  && d->get_type_value_name))
-      {
+      throw std::runtime_error(std::string("Failed resolve some symbol"
-	if (verbose)
+					   "while loading '") + file + "'.");
-	  std::cerr << "Failed to resolve some symbol while loading `"
-		    << file << "'\n";
-	delete d;
-	lt_dlexit();
-	return nullptr;
-      }
 
     if (d->have_property && d->have_property())
-      {
+      throw std::runtime_error("Models with embedded properties "
-        if (verbose)
+			       "are not supported.");
-          std::cerr << "Model with an embedded property are not supported."
-        	    << std::endl;
-        delete d;
-        lt_dlexit();
-        return nullptr;
-      }
 
+    return { d };
+  }
+
+
+  kripke_ptr
+  ltsmin_model::kripke(const atomic_prop_set* to_observe,
+		       bdd_dict_ptr dict,
+		       const formula dead, int compress) const
+  {
     spot::prop_set* ps = new spot::prop_set;
-    int errors = convert_aps(to_observe, d, dict, dead, *ps);
+    try
-    if (errors)
+      {
+	convert_aps(to_observe, iface, dict, dead, *ps);
+      }
+    catch (std::runtime_error)
       {
 	delete ps;
-	dict->unregister_all_my_variables(d);
+	dict->unregister_all_my_variables(iface.get());
-	delete d;
+	throw;
-	lt_dlexit();
-	return nullptr;
       }
 
-    return std::make_shared<spins_kripke>(d, dict, ps, dead, compress);
+    return std::make_shared<spins_kripke>(iface, dict, ps, dead, compress);
+  }
+
+  ltsmin_model::~ltsmin_model()
+  {
   }
 }

spot/ltsmin/ltsmin.hh

@@ -1,5 +1,5 @@
 // -*- coding: utf-8 -*-
-// Copyright (C) 2011, 2013, 2014, 2015 Laboratoire de Recherche et
+// Copyright (C) 2011, 2013, 2014, 2015, 2016 Laboratoire de Recherche et
 // Developpement de l'Epita (LRDE)
 //
 // This file is part of Spot, a model checking library.
@@ -24,40 +24,56 @@
 
 namespace spot
 {
+  struct spins_interface;
 
-  // \brief Load an ltsmin model, either from divine or promela.
+  class SPOT_API ltsmin_model final
-  //
+  {
-  // The filename given can be either a *.pm/*.pml/*.prom promela
+  public:
-  // source or a *.spins dynamic library compiled with "spins file".
+    ~ltsmin_model();
-  // If a promela source is supplied, this function will call spins to
+
-  // update the *.spins library only if it is not newer.
+    // \brief Load an ltsmin model, either from divine or promela.
-  //
+    //
-  // Similarly the divine models can be specified as *.dve source or
+    // The filename given can be either a *.pm/*.pml/*.prom promela
-  // *.dve or *.dve2C libraries.
+    // source or a *.spins dynamic library compiled with "spins file".
-  //
+    // If a promela source is supplied, this function will call spins to
-  // The dead parameter is used to control the behavior of the model
+    // update the *.spins library only if it is not newer.
-  // on dead states (i.e. the final states of finite sequences).
+    //
-  // If DEAD is "false", it means we are not
+    // Similarly the divine models can be specified as *.dve source or
-  // interested in finite sequences of the system, and dead state
+    // *.dve or *.dve2C libraries.
-  // will have no successor.  If DEAD is
+    //
-  // "true", we want to check finite sequences as well as infinite
+    static ltsmin_model load(const std::string& file);
-  // sequences, but do not need to distinguish them.  In that case
+
-  // dead state will have a loop labeled by true.  If DEAD is any
+    // \brief Generate a Kripke structure on-the-fly
-  // other string, this is the name a property that should be true
+    //
-  // when looping on a dead state, and false otherwise.
+    // The dead parameter is used to control the behavior of the model
-  //
+    // on dead states (i.e. the final states of finite sequences).
-  // This function returns 0 on error.
+    // If DEAD is "false", it means we are not
-  //
+    // interested in finite sequences of the system, and dead state
-  // \a file the name of the *.prom source file or the dynamic library
+    // will have no successor.  If DEAD is
-  // \a to_observe the list of atomic propositions that should be observed
+    // "true", we want to check finite sequences as well as infinite
-  //               in the model
+    // sequences, but do not need to distinguish them.  In that case
-  // \a dict the BDD dictionary to use
+    // dead state will have a loop labeled by true.  If DEAD is any
-  // \a dead an atomic proposition or constant to use for looping on
+    // other string, this is the name a property that should be true
-  //         dead states
+    // when looping on a dead state, and false otherwise.
-  // \a verbose whether to output verbose messages
+    //
-  SPOT_API kripke_ptr
+    // This function returns 0 on error.
-  load_ltsmin(const std::string& file, const bdd_dict_ptr& dict,
+    //
-	      const atomic_prop_set* to_observe,
+    // \a to_observe the list of atomic propositions that should be observed
-	      formula dead = formula::tt(),
+    //               in the model
-	      int compress = 0, bool verbose = true);
+    // \a dict the BDD dictionary to use
+    // \a dead an atomic proposition or constant to use for looping on
+    //         dead states
+    // \a compress whether to compress the states.  Use 0 to disable, 1
+    // to enable compression, 2 to enable a faster compression that only
+    // work if all variables are smaller than 2^28.
+    kripke_ptr kripke(const atomic_prop_set* to_observe,
+		      bdd_dict_ptr dict,
+		      formula dead = formula::tt(),
+		      int compress = 0) const;
+  private:
+    ltsmin_model(std::shared_ptr<const spins_interface> iface) : iface(iface)
+      {
+      }
+    std::shared_ptr<const spins_interface> iface;
+  };
 }

tests/ltsmin/modelcheck.cc

@@ -1,6 +1,6 @@
 // -*- coding: utf-8 -*-
-// Copyright (C) 2011, 2012, 2013, 2014, 2015 Laboratoire de Recherche
+// Copyright (C) 2011, 2012, 2013, 2014, 2015, 2016 Laboratoire de
-// et Developpement de l'Epita (LRDE)
+// Recherche et Developpement de l'Epita (LRDE)
 //
 // This file is part of Spot, a model checking library.
 //
@@ -216,8 +216,15 @@ checked_main(int argc, char **argv)
   if (output != DotFormula)
     {
       tm.start("loading ltsmin model");
-      model = spot::load_ltsmin(argv[1], dict, &ap, deadf,
+      try
-				compress_states, true);
+	{
+	  model = spot::ltsmin_model::load(argv[1]).kripke(&ap, dict, deadf,
+							   compress_states);
+	}
+      catch (std::runtime_error& e)
+	{
+	  std::cerr << e.what() << '\n';
+	}
       tm.stop("loading ltsmin model");
 
       if (!model)

tests/python/ltsmin.ipynb

@@ -1,7 +1,7 @@
 {
  "metadata": {
   "name": "",
-  "signature": "sha256:d5994cc04991eaf218539c16319f17128cf42be5d813785fd977ee3d991a5c00"
+  "signature": "sha256:eba4457368b676284d4696dd7afe5596d865c6f9f6f44b5fd5dc7c6585757c89"
  },
  "nbformat": 3,
  "nbformat_minor": 0,
@@ -59,7 +59,7 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "m = spot.ltsmin.load(srcdir + '/../ltsmin/finite.dve', ['P.a<1', 'P.b>2'])\n",
+      "m = spot.ltsmin.load(srcdir + '/../ltsmin/finite.dve')\n",
       "m"
      ],
      "language": "python",
@@ -69,6 +69,27 @@
        "metadata": {},
        "output_type": "pyout",
        "prompt_number": 3,
+       "text": [
+        "<spot.ltsmin.model; proxy of <Swig Object of type 'spot::ltsmin_model *' at 0x7f6990bd44e0> >"
+       ]
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "k = m.kripke([\"P.a<1\", \"P.b>2\"])\n",
+      "k"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "metadata": {},
+       "output_type": "pyout",
+       "prompt_number": 4,
        "svg": [
         "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>\n",
         "<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.1//EN\"\n",
@@ -310,11 +331,11 @@
         "</svg>\n"
        ],
        "text": [
-        "<spot.impl.kripke; proxy of <Swig Object of type 'std::shared_ptr< spot::kripke > *' at 0x7f40740974e0> >"
+        "<spot.impl.kripke; proxy of <Swig Object of type 'std::shared_ptr< spot::kripke > *' at 0x7f6990bd4600> >"
        ]
       }
      ],
-     "prompt_number": 3
+     "prompt_number": 4
     },
     {
      "cell_type": "code",
@@ -328,7 +349,7 @@
       {
        "metadata": {},
        "output_type": "pyout",
-       "prompt_number": 4,
+       "prompt_number": 5,
        "svg": [
         "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>\n",
         "<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.1//EN\"\n",
@@ -380,17 +401,17 @@
         "</svg>\n"
        ],
        "text": [
-        "<spot.impl.twa_graph; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_graph > *' at 0x7f40740977e0> >"
+        "<spot.impl.twa_graph; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_graph > *' at 0x7f6990bd4c90> >"
        ]
       }
      ],
-     "prompt_number": 4
+     "prompt_number": 5
     },
     {
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "spot.otf_product(m, a)"
+      "spot.otf_product(k, a)"
      ],
      "language": "python",
      "metadata": {},
@@ -398,7 +419,7 @@
       {
        "metadata": {},
        "output_type": "pyout",
-       "prompt_number": 5,
+       "prompt_number": 6,
        "svg": [
         "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>\n",
         "<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.1//EN\"\n",
@@ -510,20 +531,11 @@
         "</svg>\n"
        ],
        "text": [
-        "<spot.impl.twa_product; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_product > *' at 0x7f4074097720> >"
+        "<spot.impl.twa_product; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_product > *' at 0x7f6990bd49c0> >"
        ]
       }
      ],
-     "prompt_number": 5
+     "prompt_number": 6
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [],
-     "language": "python",
-     "metadata": {},
-     "outputs": [],
-     "prompt_number": 5
     }
    ],
    "metadata": {}