code: def evecs(self):
          
          if self._evecs is None:
              errMsg = "The metric eigenvectors have not been set in the "
              errMsg += "metricParameters instance."
              raise ValueError(errMsg)
          return self._evecs
docs: The eigenvectors of the parameter space.
          This is a Dictionary of numpy.matrix
          Each entry in the dictionary is as described under evals.
          Each numpy.matrix contains the eigenvectors which, with the eigenvalues
          in evals, are needed to rotate the
          coordinate system to one in which the metric is the identity matrix.