[fix] Crash when trying to print a model definition because no attribute _real

[alexAubin]

When trying to display a model description, for example just typing res.users, i get this stacktrace:

In [1]: res.users
Out[1]: ---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
File /usr/local/lib/python3.10/site-packages/IPython/core/formatters.py:770, in PlainTextFormatter.__call__(self, obj)
    763 stream = StringIO()
    764 printer = pretty.RepresentationPrinter(stream, self.verbose,
    765     self.max_width, self.newline,
    766     max_seq_length=self.max_seq_length,
    767     singleton_pprinters=self.singleton_printers,
    768     type_pprinters=self.type_printers,
    769     deferred_pprinters=self.deferred_printers)
--> 770 printer.pretty(obj)
    771 printer.flush()
    772 return stream.getvalue()

File /usr/local/lib/python3.10/site-packages/IPython/lib/pretty.py:408, in RepresentationPrinter.pretty(self, obj)
    406     meth = cls._repr_pretty_
    407     if callable(meth):
--> 408         return meth(obj, self, cycle)
    409 if (
    410     cls is not object
    411     # check if cls defines __repr__
   (...)
    417     and callable(_safe_getattr(cls, "__repr__", None))
    418 ):
    419     return _repr_pprint(obj, self, cycle)

File /usr/local/lib/python3.10/site-packages/odoo_repl/models.py:329, in ModelProxy._repr_pretty_(self, printer, _cycle)
    326 def _repr_pretty_(self, printer, _cycle):
    327     # type: (t.Any, t.Any) -> None
    328     if self._real is not None and printer.indentation == 0:
--> 329         printer.text(model_repr(self._real))
    330     else:
    331         printer.text(repr(self))

File /usr/local/lib/python3.10/site-packages/odoo_repl/models.py:36, in model_repr(obj)
     33 def model_repr(obj):
     34     # type: (t.Union[ModelProxy, BaseModel]) -> t.Text
     35     """Summarize a model's fields."""
---> 36     if obj._real != None:
     37         obj = util.unwrap(obj)

AttributeError: 'res.users' object has no attribute '_real'

Not sure what's really happening here but a naive workaround is to use getattr(obj, "_real", None) instead of obj._real and the model description then displays correctly