def METHOD_NAME(self, out_stream=PIPE):
    log.debug("Executing: %s" % str(self.cmds))
    if len(self.cmds) == 1:
        return Popen(self.cmds[0], bufsize=self.bufsize, stderr=STDOUT, stdout=out_stream, env=self.env)
    stdout = Popen(self.cmds[0], bufsize=self.bufsize, stderr=STDOUT, stdout=PIPE, env=self.env).stdout
    last = len(self.cmds) - 2
    for i, arg in enumerate(self.cmds[1:]):
        if i < last:
            stdout = Popen(arg, bufsize=self.bufsize, stdin=stdout, stderr=STDOUT, stdout=PIPE, env=self.env).stdout
        else:
            return Popen(arg, bufsize=self.bufsize, stdin=stdout, stderr=STDOUT, stdout=out_stream, env=self.env)