code: def vol_tehrahedron(poly):
      
      p_a = np.array(poly[0])
      p_b = np.array(poly[1])
      p_c = np.array(poly[2])
      p_d = np.array(poly[3])
      return abs(np.dot(
          np.subtract(p_a, p_d),
          np.cross(
              np.subtract(p_b, p_d),
              np.subtract(p_c, p_d))) / 6)
docs: volume of a irregular tetrahedron