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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def verify_notification(data):
 """ Function to verify notification came from a trusted source Returns True if verfied, False if not verified """

    pemfile = grab_keyfile(data['SigningCertURL'])
    cert = crypto.load_certificate(crypto.FILETYPE_PEM, pemfile)
    signature = base64.decodestring(six.b(data['Signature']))

    if data['Type'] == "Notification":
        hash_format = NOTIFICATION_HASH_FORMAT
    else:
        hash_format = SUBSCRIPTION_HASH_FORMAT

    try:
        crypto.verify(
            cert, signature, six.b(hash_format.format(**data)), 'sha1')
    except crypto.Error:
        return False
    return True