code: def vol_prefactor(n, p=2.):
      
  
      p *= 1.  # convert to float in case user inputs an integer
      f = (2 * special.gamma(1./p + 1.))**n / special.gamma(n/p + 1)
  
      return f
docs: Returns the volume constant for an `n`-dimensional sphere with an
      :math:`L^p` norm. The constant is defined as::
  
          f = (2. * Gamma(1./p + 1))**n / Gamma(n/p + 1.)
  
      By default the `p=2.` norm is used (i.e. the standard Euclidean norm).