Creates a new App instance using the specified options
and the app name. If an instance already exists by the same
app name a ValueError is raised.
If options are not provided an attempt is made to load the options from the environment.
This is done by looking up the FIREBASE_CONFIG environment variable. If the value of
the variable starts with "{", it is parsed as a JSON object. Otherwise it is treated
as a file name and the JSON content is read from the corresponding file.
Use this function whenever a new App instance is required. Do not directly invoke the
App constructor.
Parameters:
credential – A credential object used to initialize the SDK (optional). If none is provided,
Google Application Default Credentials are used.
options – A dictionary of configuration options (optional). Supported options include
databaseURL, storageBucket, projectId, databaseAuthVariableOverride,
serviceAccountId and httpTimeout. If httpTimeout is not set, the SDK uses
a default timeout of 120 seconds.