code: def mfpt(totflux, pi, qminus):
      r
      return dense.tpt.mfpt(totflux, pi, qminus)
docs: r"""Mean first passage time for reaction A to B.
  
      Parameters
      ----------
      totflux : float
          The total flux between reactant and product
      pi : (M,) ndarray
          Stationary distribution
      qminus : (M,) ndarray
          Backward comittor
  
      Returns
      -------
      tAB : float
          The mean first-passage time for the A to B reaction
  
      See also
      --------
      rate
  
      Notes
      -----
      Equal to the inverse rate, see [1].
  
      References
      ----------
      .. [1] F. Noe, Ch. Schuette, E. Vanden-Eijnden, L. Reich and
          T. Weikl: Constructing the Full Ensemble of Folding Pathways
          from Short Off-Equilibrium Simulations.
          Proc. Natl. Acad. Sci. USA, 106, 19011-19016 (2009)