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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 header_length(bytearray):
 """Return the length of s when it is encoded with base64."""

    groups_of_3, leftover = divmod(len(bytearray), 3)
    # 4 bytes out for each 3 bytes (or nonzero fraction thereof) in.
    n = groups_of_3 * 4
    if leftover:
        n += 4
    return n