@classmethod<EOL><INDENT>def ids(cls, filter=None, **kwargs):<DEDENT>
from mongoframes.queries import Condition, Group, to_refs<EOL>if isinstance(filter, (Condition, Group)):<EOL><INDENT>filter = filter.to_dict()<EOL><DEDENT>documents = cls.get_collection().find(<EOL>to_refs(filter),<EOL>projection={'<STR_LIT>': True},<EOL>**kwargs<EOL>)<EOL>return [d['<STR_LIT>'] for d in list(documents)]<EOL>
Return a list of Ids for documents matching the filter