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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 format_version(epoch, version, release):
    '''
    Formats a version string for list_pkgs.
    '''
    full_version = '{0}:{1}'.format(epoch, version) if epoch else version
    if release:
        full_version += '-{0}'.format(release)
    return full_version