code: def _remove_bottleneck(net_flux, path):
      
      net_flux = copy.copy(net_flux)
  
      bottleneck_ind = net_flux[path[:-1], path[1:]].argmin()
  
      net_flux[path[bottleneck_ind], path[bottleneck_ind + 1]] = 0.0
  
      return net_flux
docs: Internal function for modifying the net flux matrix by removing
      a particular edge, corresponding to the bottleneck of a particular
      path.