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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 stream_copy(source, destination, chunk_size=512 * 1024):
 """Copy all data from the source stream into the destination stream in chunks of size chunk_size :return: amount of bytes written"""

    br = 0
    while True:
        chunk = source.read(chunk_size)
        destination.write(chunk)
        br += len(chunk)
        if len(chunk) < chunk_size:
            break
    # END reading output stream
    return br