code: def get_field(field):
      
      if isinstance(field, djmodels.fields.Field):
          return field
      elif isinstance(field, basestring):
          field = field.split('.')
          if len(field) == 3:
              model = get_model(app=field[0], model=field[1])
          elif len(field) == 2:
              model = get_model(app=DEFAULT_APP, model=field[0])
          else:
              return None
              raise NotImplementedError("Unknown default model name. Don't know where to look for field %s" % '.'.join(field)) 
          field = model._meta.get_field(field[-1])
      return field
docs: Return a field object based on a dot-delimited app.model.field name