code: def _get_param_names(cls):
          
          # fetch the constructor or the original constructor before
          # deprecation wrapping if any
          init = getattr(cls.__init__, 'deprecated_original', cls.__init__)
          if init is object.__init__:
              # No explicit constructor to introspect
              return []
  
          # introspect the constructor arguments to find the model parameters
          # to represent
          args, varargs, kw, default = getargspec_no_self(init)
          if varargs is not None:
              raise RuntimeError("scikit-learn estimators should always "
                                 "specify their parameters in the signature"
                                 " of their __init__ (no varargs)."
                                 " %s doesn't follow this convention."
                                 % (cls, ))
          args.sort()
          return args
docs: Get parameter names for the estimator