code: def sph_harm_prefactor(l, m):
      """Computes the constant pre-factor for the spherical harmonic of degree l and order m.
      Parameters
      ----------
          l: int
              Degree of the spherical harmonic. l >= 0
          m: int
              Order of the spherical harmonic. -l <= m <= l
      Returns
      -------
          factor: float
      """
      # sqrt((2*l+1)/4*pi * (l-m)!/(l+m)! )
      return (
          (2 * l + 1)
          / (4 * np.pi)
          * np.math.factorial(l - abs(m))
          / np.math.factorial(l + abs(m))
      ) ** 0.5
  
file_path: DIG/dig/threedgraph/method/pronet/features.py
imports: import torch
  import sympy
  import numpy
  from scipy.optimize import brentq
  from scipy import special
label_desc: Use image node_id 5 for calling a global function with example usage: sph_harm_prefactor(l, m) and returns: unknown