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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 pandoc_version():
 """Pandoc's version number"""

    version = pandoc(u'--version').splitlines()[0].split()[1]
    if parse_version(version) < parse_version('2.7.2'):
        raise PandocError('Please install pandoc>=2.7.2 (found version {})'.format(version))

    return version