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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 close(self):
        '''Closes the handle, if it is still open.

        Usually, you should prefer using the handle as a context manager to
        calling :meth:`close` manually.'''
        if self.handle is not None:
            self.close_handle(self.nsdk, self.handle)
            self.handle = None