code: def vol_tetra(vt1, vt2, vt3, vt4):
      
      vol_tetra = np.abs(np.dot((vt1 - vt4),
                                np.cross((vt2 - vt4), (vt3 - vt4)))) / 6
      return vol_tetra
docs: Calculate the volume of a tetrahedron, given the four vertices of vt1,
      vt2, vt3 and vt4.
      Args:
          vt1 (array-like): coordinates of vertex 1.
          vt2 (array-like): coordinates of vertex 2.
          vt3 (array-like): coordinates of vertex 3.
          vt4 (array-like): coordinates of vertex 4.
      Returns:
          (float): volume of the tetrahedron.