docs: def create_cell_volumes(self):
          """Computes the volumes of the "cells" in the mesh.
          """
          self.cell_volumes = numpy.array(
              [
                  abs(
                      self.node_coords[cell["nodes"]][1]
                      - self.node_coords[cell["nodes"]][0]
                  )
                  for cell in self.cells
              ]
          )
          return