Return the __init__ initializer assignment block

def initializers(self, prefix: Optional[str] = None) -> List[str]:
        """ Return the __init__ initializer assignment block """
        if self._type_reference:
            # This assumes that references are to things that have initializers
            # TODO: Remove this check once we are certian things are good
            ref = self._context.reference(self._type_reference)
            if not getattr(ref, 'signatures', None):
                raise NotImplementedError("Reference to " + self._type_reference + " is not valid")
            return self._context.reference(self._type_reference).initializers(prefix)
        else:
            return flatten([self._initializer_for(rn, cn, prefix) for rn, cn in self._names.items()])