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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 install_cmd(argv):
    '''Use Pythonz to download and build the specified Python version'''
    installer = InstallCommand()
    options, versions = installer.parser.parse_args(argv)
    if len(versions) != 1:
        installer.parser.print_help()
        sys.exit(1)
    else:
        try:
            actual_installer = PythonInstaller.get_installer(versions[0], options)
            return actual_installer.install()
        except AlreadyInstalledError as e:
            print(e)