def _get_relation_type(self, field: "BaseField") -> RelationType:
        """
        Returns type of the relation declared on a field.

        :param field: field with relation declaration
        :type field: BaseField
        :return: type of the relation defined on field
        :rtype: RelationType
        """
        if field.is_multi:
            return RelationType.MULTIPLE
        if field.is_through:
            return RelationType.THROUGH
        return RelationType.PRIMARY if not field.virtual else RelationType.REVERSE

        Returns type of the relation declared on a field.

        :param field: field with relation declaration
        :type field: BaseField
        :return: type of the relation defined on field
        :rtype: RelationType
        
ormar/relations/relation_manager.py