code: def bind(self, extension: Extension) -> 'DictMentor':
          
          if not Extension.is_valid_extension(extension):
              raise ValueError("Cannot bind extension due to missing interface requirements")
          self._extensions.append(extension)
  
          return self
docs: Add any predefined or custom extension.
  
          Args:
              extension: Extension to add to the processor.
  
          Returns:
              The DictMentor itself for chaining.