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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 exec_output(cls, command, shell=True, encoding='utf-8'):
 """ Return execution output :param encoding: charset used to decode the stdout :type encoding: str :return: the return of the command :rtype: unicode string """

        proc = Popen(command, shell=shell, stdout=PIPE)
        stdout, _stderr = proc.communicate()
        if proc.returncode == 0:
            return stdout.decode(encoding)

        return ''