def user_groups(self, ldap_user, group_search):
return []<EOL>
Returns a list of group_info structures, each one a group to which
ldap_user belongs. group_search is an LDAPSearch object that returns all
of the groups that the user might belong to. Typical implementations
will apply additional filters to group_search and return the results of
the search. ldap_user represents the user and has the following three
properties:

dn: the distinguished name
attrs: a dictionary of LDAP attributes (with lists of values)
connection: an LDAPObject that has been bound with credentials

This is the primitive method in the API and must be implemented.