<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def load_umatrix(self, filename):
 """Load the umatrix from a file to the Somoclu object. :param filename: The name of the file. :type filename: str. """


        self.umatrix = np.loadtxt(filename, comments='%')
        if self.umatrix.shape != (self._n_rows, self._n_columns):
            raise Exception("The dimensions of the U-matrix do not "
                            "match that of the map")