code: def get_relationships_on_date(self, from_, to):
          
          # Implemented from template for
          # osid.relationship.RelationshipLookupSession.get_relationships_on_date
          relationship_list = []
          for relationship in self.get_relationships():
              if overlap(from_, to, relationship.start_date, relationship.end_date):
                  relationship_list.append(relationship)
          return objects.RelationshipList(relationship_list, runtime=self._runtime)
docs: Gets a ``RelationshipList`` effective during the entire given date range inclusive but not confined to the date range.
  
          arg:    from (osid.calendaring.DateTime): starting date
          arg:    to (osid.calendaring.DateTime): ending date
          return: (osid.relationship.RelationshipList) - the relationships
          raise:  InvalidArgument - ``from is greater than to``
          raise:  NullArgument - ``from`` or ``to`` is ``null``
          raise:  OperationFailed - unable to complete request
          raise:  PermissionDenied - authorization failure
          *compliance: mandatory -- This method must be implemented.*