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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 set_version(version):
 """ set the version in the projects root module """


    with open(FILENAME) as pythonfile:
        content = pythonfile.read()

    output = re.sub(RE_VERSION, r"\1'{}'".format(version), content)

    if content == output:
        error('failed updating {}'.format(FILENAME))

    with open(FILENAME, 'w') as pythonfile:
        pythonfile.write(output)