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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 double_sha256(ba):
 """ Perform two SHA256 operations on the input. Args: ba (bytes):
 data to hash. Returns: str: hash as a double digit hex string. """

    d1 = hashlib.sha256(ba)
    d2 = hashlib.sha256()
    d1.hexdigest()
    d2.update(d1.digest())
    return d2.hexdigest()