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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 sign_raw_data(raw_data, privatekey_hex):
 """ Sign a string of data. Returns signature as a base64 string """

    if not isinstance(raw_data, (str, unicode)):
        raise ValueError("Data is not a string")

    raw_data = str(raw_data)

    si = ECSigner(privatekey_hex)
    si.update(raw_data)
    return si.finalize()