'**SUMMARY**
Find faces in the image using FaceRecognizer and predict their class.
**PARAMETERS**
* *recognizer*   - Trained FaceRecognizer object
**EXAMPLES**
>>> cam = Camera()
>>> img = cam.getImage()
>>> recognizer = FaceRecognizer()
>>> recognizer.load("training.xml")
>>> print img.recognizeFace(recognizer)'

def recognizeFace(self, recognizer=None):

    try:
        import cv2
        if (not hasattr(cv2, 'createFisherFaceRecognizer')):
            warnings.warn('OpenCV    >=    2.4.4    required    to    use    this.')
            return None
    except ImportError:
        warnings.warn('OpenCV    >=    2.4.4    required    to    use    this.')
        return None
    if (not isinstance(recognizer, FaceRecognizer)):
        warnings.warn('SimpleCV.Features.FaceRecognizer    object    required.')
        return None
    (w, h) = recognizer.imageSize
    label = recognizer.predict(self.resize(w, h))
    return label
