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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 start(self, trunk_type):
 """Type of internal network trunk. in trunk_type of type str Type of internal network trunk. """

        if not isinstance(trunk_type, basestring):
            raise TypeError("trunk_type can only be an instance of type basestring")
        self._call("start",
                     in_p=[trunk_type])