Gets an RSAKey object for the private key file so that we can
        copy files without logging in with user/password.

def _get_pkey(self):
        """Gets an RSAKey object for the private key file so that we can
        copy files without logging in with user/password."""
        keypath = self.config.server["pkey"]
        with open(os.path.expanduser(keypath)) as f:
            pkey = paramiko.RSAKey.from_private_key(f)

        return pkey