'Converts a v3 Filter to a v1 PropertyFilter.
Args:
v3_filter: a datastore_pb.Filter
v1_property_filter: a googledatastore.PropertyFilter to populate
Raises:
InvalidConversionError if the filter cannot be converted'

def _v3_filter_to_v1_property_filter(self, v3_filter, v1_property_filter):

    check_conversion((v3_filter.property_size() == 1), 'invalid    filter')
    check_conversion((v3_filter.op() <= 5), ('unsupported    filter    op:    %d' % v3_filter.op()))
    v1_property_filter.Clear()
    v1_property_filter.op = v3_filter.op()
    v1_property_filter.property.name = v3_filter.property(0).name()
    self._entity_converter.v3_property_to_v1_value(v3_filter.property(0), True, v1_property_filter.value)
