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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 get_cmd_handler(self, cmd):
 """ Return an handler for cmd. The handler and the command should have the same name. See class description for more info about handlers. Args: cmd (str):
 The name of the command Returns: callable: which handles cmd Raises: lago.build.BuildException: If an handler for cmd doesn't exist """

        cmd = cmd.replace('-', '_')
        handler = getattr(self, cmd, None)
        if not handler:
            raise BuildException(
                'Command {} is not supported as a '
                'build command'.format(cmd)
            )
        return handler