Test if path exists.
Test if path exists as (and in this order):
a local file.
a remote URL that has been downloaded and stored locally in the
a remote URL that has not been downloaded, but is valid and accessible.
Can be a local file or a remote URL.
True if path exists.
When path is an URL,
existswill return True if it’s either stored locally in the
DataSourcedirectory, or is a valid remote URL.
DataSourcedoes not discriminate between the two, the file is accessible if it exists in either location.