code: def _label_faces(self):
          r'''
          Label the pores sitting on the faces of the domain in accordance with
          the conventions used for cubic etc.
          '''
          coords = sp.around(self['pore.coords'], decimals=10)
          min_labels = ['front', 'left', 'bottom']
          max_labels = ['back', 'right', 'top']
          min_coords = sp.amin(coords, axis=0)
          max_coords = sp.amax(coords, axis=0)
          for ax in range(3):
              self['pore.' + min_labels[ax]] = coords[:, ax] == min_coords[ax]
              self['pore.' + max_labels[ax]] = coords[:, ax] == max_coords[axf _label_faces(self):
          r'''
          Label the pores sitting on the faces of the domain in accordance with
          the conventions used for cubic etc.
          '''
          coords = sp.around(self['pore.coords'], decimals=10)
          min_labels = ['front', 'left', 'bottom']
          max_labels = ['back', 'right', 'top']
          min_coords = sp.amin(coords, axis=0)
          max_coords = sp.amax(coords, axis=0)
          for ax in range(3):
              self['pore.' + min_labels[ax]] = coords[:, ax] == min_coords[ax]
              self['pore.' + max_labels[ax]] = coords[:, ax] == max_coords[ax]
docs: r'''
          Label the pores sitting on the faces of the domain in accordance with
          the conventions used for cubic etc.