new_contents: # coding=utf-8
  from __future__ import absolute_import
  
  import sqlalchemy as sa
  
  from wtforms_alchemy import utils
  from tests import FormRelationsTestCase
  
  class TestUtils(FormRelationsTestCase):
      def create_models(self):
          class Band(self.base):
              __tablename__ = 'band'
              id = sa.Column(sa.Integer, primary_key=True)
              name = sa.Column(sa.Unicode(255), nullable=False)
  
          class Person(self.base):
              __tablename__ = 'person'
              id = sa.Column(sa.Integer, primary_key=True)
              name = sa.Column(sa.Unicode(255), nullable=False)
  
          class BandMember(self.base):
              __tablename__ = 'band_members'
              band_id = sa.Column(sa.Integer, sa.ForeignKey(Band.id),
                                  primary_key=True)
              band = sa.orm.relationship(Band, backref='members')
              person_id = sa.Column(sa.Integer, sa.ForeignKey(Person.id),
                                    primary_key=True)
              person = sa.orm.relationship(Person,
                                           backref=sa.orm.backref('band_role',
                                                                  uselist=False))
              role = sa.Column(sa.Unicode(255), nullable=False)
  
              def __repr__(self):
                  fmt = '<BandMember band_id={} person_id={} at {:x}>'
                  return fmt.format(repr(self.band_id), repr(self.person_id),
                                    id(self))
  
          self.Band = Band
          self.Person = Person
          self.BandMember = BandMember
  
      def create_forms(self):
          pass
  
      def test_find_entity(self):
          band = self.Band(name=u'The Furious')
          self.session.add(band)
          singer = self.Person(name=u'Paul Insane')
          role = self.BandMember(band=band, person=singer, role=u'singer')
          guitarist = self.Person(name=u'John Crazy')
          role = self.BandMember(band=band, person=guitarist, role=u'guitar')
          self.session.commit()
  
          sing_data = dict(band_id=band.id, person_id=singer.id, role=u'singer')
          guitar_data = dict(band_id=band.id, person_id=guitarist.id,
                             role=u'guitar')
  
          assert (utils.find_entity(band.members, self.BandMember, sing_data)
                  is singer.band_role)
          assert (utils.find_entity(band.members, self.BandMember, guitar_data)
                  is guitarist.band_role)
  
subject: test utils.find_entity