code: function methodSig () {
    return arrayify(this.params).filter(function (param) {
      return param.name && !/\./.test(param.name)
    }).map(function (param) {
      if (param.variable) {
        return param.optional ? '[...' + param.name + ']' : '...' + param.name
      } else {
        return param.optional ? '[' + param.name + ']' : param.name
      }
    }).join(', ')
  }
docs: Returns the method signature, e.g. `(options, [onComplete])`
  @this {identifier}
  @returns {string}
  @category Returns string
  @static