def date_extract_sql(self, lookup_type, field_name):
    "\n        Given a lookup_type of 'year', 'month' or 'day', returns the SQL that\n        extracts a value from the given date field field_name.\n        "
    raise NotImplementedError()
Given a lookup_type of 'year', 'month' or 'day', returns the SQL that
extracts a value from the given date field field_name.
def date_extract_sql(self, lookup_type, field_name):
    "\n        Given a lookup_type of 'year', 'month' or 'day', returns the SQL that\n        extracts a value from the given date field field_name.\n        "
    raise NotImplementedError()