'Revokes a grant. You can revoke a grant to actively deny
operations that depend on it.
:type key_id: string
:param key_id: Unique identifier of the key associated with the grant.
:type grant_id: string
:param grant_id: Identifier of the grant to be revoked.'

def revoke_grant(self, key_id, grant_id):

    params = {'KeyId': key_id, 'GrantId': grant_id}
    return self.make_request(action='RevokeGrant', body=json.dumps(params))
