def get_oauth_token_key_name(self, provider):
        """
        Returns the token_key name for the oauth provider
        if none is configured defaults to oauth_token
        this is configured using OAUTH_PROVIDERS and token_key key.
        """
        for _provider in self.oauth_providers:
            if _provider["name"] == provider:
                return _provider.get("token_key", "oauth_token")

        Returns the token_key name for the oauth provider
        if none is configured defaults to oauth_token
        this is configured using OAUTH_PROVIDERS and token_key key.
        
flask_appbuilder/security/manager.py