def _from_signer_and_info(cls, signer, info, **kwargs):
        """Creates a Credentials instance from a signer and service account
        info.

        Args:
            signer (google.auth.crypt.Signer): The signer used to sign JWTs.
            info (Mapping[str, str]): The service account info.
            kwargs: Additional arguments to pass to the constructor.

        Returns:
            google.auth.jwt.Credentials: The constructed credentials.

        Raises:
            ValueError: If the info is not in the expected format.
        """
        kwargs.setdefault('subject', info['client_email'])
        kwargs.setdefault('issuer', info['client_email'])
        return cls(signer, **kwargs)
Creates a Credentials instance from a signer and service account
        info.

        Args:
            signer (google.auth.crypt.Signer): The signer used to sign JWTs.
            info (Mapping[str, str]): The service account info.
            kwargs: Additional arguments to pass to the constructor.

        Returns:
            google.auth.jwt.Credentials: The constructed credentials.

        Raises:
            ValueError: If the info is not in the expected format.