def get_application_default scope = nil, options = {}
      creds = DefaultCredentials.from_env(scope, options) ||
              DefaultCredentials.from_well_known_path(scope, options) ||
              DefaultCredentials.from_system_default_path(scope, options)
      return creds unless creds.nil?
      unless GCECredentials.on_gce? options
        # Clear cache of the result of GCECredentials.on_gce?
        GCECredentials.unmemoize_all
        raise NOT_FOUND_ERROR
      end
      GCECredentials.new
    end
def get_application_default scope = nil, options = {}
      creds = DefaultCredentials.from_env(scope, options) ||
              DefaultCredentials.from_well_known_path(scope, options) ||
              DefaultCredentials.from_system_default_path(scope, options)
      return creds unless creds.nil?
      unless GCECredentials.on_gce? options
        # Clear cache of the result of GCECredentials.on_gce?
        GCECredentials.unmemoize_all
        raise NOT_FOUND_ERROR
      end
      GCECredentials.new
    end
Obtains the default credentials implementation to use in this
 environment.

 Use this to obtain the Application Default Credentials for accessing
 Google APIs.  Application Default Credentials are described in detail
 at http://goo.gl/IUuyuX.

 If supplied, scope is used to create the credentials instance, when it can
 be applied.  E.g, on google compute engine and for user credentials the
 scope is ignored.

 @param scope [string|array|nil] the scope(s) to access
 @param options [Hash] Connection options. These may be used to configure
     the `Faraday::Connection` used for outgoing HTTP requests. For
     example, if a connection proxy must be used in the current network,
     you may provide a connection with with the needed proxy options.
     The following keys are recognized:
     * `:default_connection` The connection object to use for token
       refresh requests.
     * `:connection_builder` A `Proc` that creates and returns a
       connection to use for token refresh requests.
     * `:connection` The connection to use to determine whether GCE
       metadata credentials are available.