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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 which(cls, cmd):
 """Return an absolute path of the command. It behaves like "which command". """

        abs_path_cmd = None
        if sys.version_info >= (3, 3):
            abs_path_cmd = shutil.which(cmd)
        else:
            abs_path_cmd = find_executable(cmd)
        return abs_path_cmd