code: func (m Method) ParamTypes() []string {
  	sig := m.signature()
  	types := m.listTypes(sig.Params())
  	n := len(types)
  	if n > 0 && sig.Variadic() {
  		types[n-1] = strings.Replace(types[n-1], "[]", "...", 1)
  	}
  	return types
  }
docs: // ParamTypes returns the list of types for the params