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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 dropna(self):
        '''
        Remove rows and cols that have no assigned measurements.
        Return new instance.
        '''
        new = self.copy()
        tmp = self._dict2DF(self, nan, True)
        new.row_labels = list(tmp.index)
        new.col_labels = list(tmp.columns)
        return new