Revert type checking commit from July

          # self.lmp = self.lib.lammps_open_no_mpi(0,None)

    else:

      if isinstance(ptr,lammps):

      self.opened = 0

      # magic to convert ptr to ctypes ptr

      pythonapi.PyCObject_AsVoidPtr.restype = c_void_p

      pythonapi.PyCObject_AsVoidPtr.argtypes = [py_object]

      self.lmp = c_void_p(pythonapi.PyCObject_AsVoidPtr(ptr))

      else:

        self.lmp = None

        raise TypeError('Unsupported type passed as "ptr"')

  def __del__(self):

    if self.lmp and self.opened: self.lib.lammps_close(self.lmp)