code: function(auth, options) {
        options = opts(this, options);
        options.applevel = true;
  
        var payload = JSON.stringify({
          email: auth.email,
          username: auth.username,
          password: auth.password,
          credentials: {
            password: auth.new_password,
            username: auth.new_username,
            email: auth.new_email
          }
        });
  
        return new APICall({
          action: 'account/credentials',
          type: 'POST',
          data: payload,
          options: options,
          processResponse: APICall.basicResponse
        });
      }
docs: Change a user's credentials: user/email and/or password
  @param {object} auth An object with email, username, password, and new_password, new_email, new_username fields.
  @param {object} [options] Override defaults set on WebService. See WebService constructor for parameters.
  @return {APICall} An APICall instance for the web service request used to attach events.
  
  @function
  @name changeCredentials
  @memberOf WebService.prototype