private static boolean isMethodFromAdditionalInterfaces(Type mockType, Method method) {
    //We have a method from additional interfaces of the mock, because there was no common type found.
    return GenericTypeReflectorUtil.getExactSuperType(mockType, method.getDeclaringClass()) == null;
  }
@param mockType the mocked type
@param method   the intercepted method
@return <code>true</code>, if the method is not part of the hierarchy of the mocked type.
spock-core/src/main/java/org/spockframework/mock/runtime/StaticMockMethod.java