code: def bind_to_constructor(self, cls, constructor):
          
          self._check_class(cls)
          if constructor is None:
              raise InjectorException('Constructor cannot be None, key=%s' % cls)
  
          self._bindings[cls] = _ConstructorBinding(constructor)
          logger.debug('Bound %s to a constructor %s', cls, constructor)
          return self
docs: Bind a class to a callable singleton constructor.