code: def updateIntensities(self, fiContainer, iKey='intensity'):
          
          for fgi in listvalues(self.container):
              intensities = list()
              specfileIds = {i: j for i, j in zip(fgi.specfiles, fgi.featureIds)}
              for specfile in self._matrixTemplate:
                  if specfile in specfileIds:
                      fi = fiContainer.getItem(specfile, specfileIds[specfile])
                      intensities.append(getattr(fi, iKey))
                  else:
                      intensities.append(None)
              fgi.intensities = intensities
docs: #TODO: docstring
          :param fiContainer:
          :param iKey: Attribute name of :class:`Fi` that contains the feature
              intensity or an abundance measure. Default "intensity"