def unify(self, typingctx, other):
        """
        Unify this with the *other* dictionary.
        """
        # If other is dict
        if isinstance(other, DictType):
            if not other.is_precise():
                return self
            else:
                ukey_type = self.key_type == other.key_type
                uvalue_type = self.value_type == other.value_type
                if ukey_type and uvalue_type:
                    siv = self.initial_value
                    oiv = other.initial_value
                    siv_none = siv is None
                    oiv_none = oiv is None
                    if not siv_none and not oiv_none:
                        if siv == oiv:
                            return DictType(self.key_type, other.value_type,
                                            siv)
                    return DictType(self.key_type, other.value_type)

        Unify this with the *other* dictionary.
        
numba/core/types/containers.py