When an OAuth2 call fails, raise_from_error loops through all defined exceptions in errors.py to find one that matches the returned error code. However, the invalid_request error code is defined on a base class InvalidRequestFatalError that is implemented by several specific errors. The result is that, when an invalid_request happens, a random class is raised to the calling client.

For example, I hade the following happen:

oauthlib.oauth2.rfc6749.errors.InvalidClientIdError: (invalid_request) Missing required parameter: refresh_token

(which is obviously not an InvalidClientIdError)