new_contents: # coding: utf-8
  """Source: lookup_www.common.models (but just a subset)
  
  """
  from __future__ import absolute_import, print_function, unicode_literals
  
  
  ###############################################################################
  # MIXINS
  ###############################################################################
  
  
  class ValidateModelMixin(object):
  
      """Make :meth:`save` call :meth:`full_clean`.
  
      .. warning:
          This should be the left-most mixin/super-class of a model.
  
      Do you think Django models ``save`` method will validate all fields
      (i.e. call ``full_clean``) before saving or any time at all? Wrong!
  
      I discovered this awful truth when I couldn't understand why
      a model object with an email field (without `blank=True`) could be
      saved with an empty string as email address.
  
      More info:
  
      * "Why doesn't django's model.save() call full clean?"
          http://stackoverflow.com/questions/4441539/
      * "Model docs imply that ModelForm will call Model.full_clean(),
          but it won't."
          https://code.djangoproject.com/ticket/13100
  
      """
  
      def save(self, *args, **kwargs):
          """Call :meth:`full_clean` before saving."""
          self.full_clean()
          super(ValidateModelMixin, self).save(*args, **kwargs)
  
subject: add module `models`, including 'ValidateModelMixin`