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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 add_cli(self, prefix, other_cli):
 """Adds the functionality of the other CLI to this one, where all commands to the other CLI are prefixed by the given prefix plus a hyphen. e.g. To execute command `greet anson 5` on other cli given prefix cli2, you can execute the following with this CLI: cli2 greet anson 5 """

        if prefix not in self.clis and prefix not in self.cmds:
            self.clis[prefix] = other_cli
        else:
            raise ValueError('Attempting to overwrite cmd or extern CLI: %s' % prefix)