def __init__(self, expression, column_name, data_type):
        if not hasattr(column_name, 'resolve_expression'):
            column_name = Value(column_name)

        try:
            output_field = self.TYPE_MAP[data_type]
        except __HOLE__:
            raise ValueError("Invalid data_type '{}'".format(data_type))

        if data_type == 'BINARY':
            output_field = output_field()  # no spec
        else:
            output_field = output_field

        super(ColumnGet, self).__init__(expression, column_name,
                                        output_field=output_field,
                                        data_type=data_type)
dataset/ETHPy150Open adamchainz/django-mysql/django_mysql/models/functions.py/ColumnGet.__init__