code: function clean(method) {
    for (let m of methods) {
      if (new RegExp(m, 'i').test(method)) {
        return m;
      }
    }
  
    throw new Error(`Invalid method name: ${method}`);
  }
docs: Returns a clean, lower-case method name.
  
  @param {String} method The method to check and clean.
  
  @returns {String} The clean method name.