(self, item)
return item in self._indices or self._get_equivalent(item) is not None
Return `True` if the item (`str`, `int`, :class:`Variable`) is
        in the domain.
Return `True` if the item (`str`, `int`, :class:`Variable`) is
        in the domain.
Return True if the item ( str int : class : Variable ) is in the domain .
def __contains__(self, item):
        """
        Return `True` if the item (`str`, `int`, :class:`Variable`) is
        in the domain.
        """
        return item in self._indices or self._get_equivalent(item) is not None
def __contains__ ( self , item ) : return item in self . _indices or self . _get_equivalent ( item ) is not None