Jupyter error

---------------------------------------------------------------------------
Exception                                 Traceback (most recent call last)
/home/user/.local/lib/python3.5/site-packages/IPython/core/formatters.py in __call__(self, obj)
    697                 type_pprinters=self.type_printers,
    698                 deferred_pprinters=self.deferred_printers)
--> 699             printer.pretty(obj)
    700             printer.flush()
    701             return stream.getvalue()

/home/user/.local/lib/python3.5/site-packages/IPython/lib/pretty.py in pretty(self, obj)
    381                             if callable(meth):
    382                                 return meth(obj, self, cycle)
--> 383             return _default_pprint(obj, self, cycle)
    384         finally:
    385             self.end_group()

/home/user/.local/lib/python3.5/site-packages/IPython/lib/pretty.py in _default_pprint(obj, p, cycle)
    501     if _safe_getattr(klass, '__repr__', None) not in _baseclass_reprs:
    502         # A user-provided repr. Find newlines and replace them with p.break_()
--> 503         _repr_pprint(obj, p, cycle)
    504         return
    505     p.begin_group(1, '<')

/home/user/.local/lib/python3.5/site-packages/IPython/lib/pretty.py in _repr_pprint(obj, p, cycle)
    692     """A pprint that just redirects to the normal repr function."""
    693     # Find newlines and replace them with p.break_()
--> 694     output = repr(obj)
    695     for idx,output_line in enumerate(output.splitlines()):
    696         if idx:

<ipython-input-7-3ed0d2189fc5> in __repr__(self)
      1 class Custom:
      2     def __repr__(self):
----> 3         raise Exception("oops called repr")
      4 
      5     def _repr_html_(self):

Exception: oops called repr