old_contents: """ Deserializer definition."""
  from django.forms import ModelForm
  import ast
  
  from .utils import classproperty
  
  
  class DeserializerMeta(object):
  
      @classproperty
      def form(cls):
          if cls.model is not None:
              class Form(ModelForm):
                  class Meta:
                      model = cls.model
              return Form()
          else:
              return None
  
  
  class Deserializer(object):
  
      Meta = DeserializerMeta
  
      @classmethod
      def load_documents(cls, input):
          """ Given document get model.
  
          :param str input: documents
  
          """
          data = ast.literal_eval(input)
          return data
  
new_contents: """ Deserializer definition."""
  from django.forms import ModelForm
  import ast
  
  from .utils import classproperty
  
  
  class DeserializerMeta(object):
  
      @classproperty
      def form(cls, fields=None):
          if cls.model is not None:
  
              class Form(ModelForm):
                  class Meta:
                      fields = list(fields or cls.fields_own.keys())
                      model = cls.model
              return Form()
          else:
              return None
  
  
  class Deserializer(object):
  
      Meta = DeserializerMeta
  
      @classmethod
      def load_documents(cls, input):
          """ Given document get model.
  
          :param str input: documents
  
          """
          data = ast.literal_eval(input)
          return data
  
subject: update fields for form. Generate partial model form