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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 endian_swap_words(source):
 """ Endian-swap each word in 'source' bitstring """

    assert len(source) % 4 == 0
    words = "I" * (len(source) // 4)
    return struct.pack("<" + words, *struct.unpack(">" + words, source))