docs: def get_default(self):
          """
          Return the default value to use when validating data if no input
          is provided for this field.
  
          If a default has not been set for this field then this will simply
          return `empty`, indicating that no value should be set in the
          validated data for this field.
          """
          if self.default is empty:
              raise SkipField()
          if callable(self.default):
              if hasattr(self.default, 'set_context'):
                  self.default.set_context(self)
              return self.default()
          return self.default