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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 md5(source):
 """Return MD5 Checksum """

    # fix passing char '+' from source
    source = source.replace("%2B", "+")
    with open(source) as file_to_check:
        data = file_to_check.read()
        return hashlib.md5(data).hexdigest()