Returns `entity` but will make an API call if necessary.

async def get_entity(self):
        """
        Returns `entity` but will make an API call if necessary.
        """
        if not self.entity and await self.get_input_entity():
            try:
                self._entity =\
                    await self._client.get_entity(self._input_entity)
            except ValueError:
                pass

        return self._entity