code: def pltvol(vrtces, plates):
      
      nv = ctypes.c_int(len(vrtces))
      vrtces = stypes.toDoubleMatrix(vrtces)
      np = ctypes.c_int(len(plates))
      plates = stypes.toIntMatrix(plates)
      return libspice.pltvol_c(nv, vrtces, np, plates)
docs: Compute the volume of a three-dimensional region bounded by a 
      collection of triangular plates. 
      
      https://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/pltvol_c.html
   
      :param vrtces: Array of vertices.
      :type vrtces: Nx3-Element Array of floats
      :param plates: Array of plates. 
      :type plates: Nx3-Element Array of ints 
      :return: the volume of the spatial region bounded by the plates. 
      :rtype: float