code: def ret_normalized_vec(vec, length):
      """Normalize a vector in L2 (Euclidean unit norm).
  
      Parameters
      ----------
      vec : list of (int, number)
          Input vector in BoW format.
      length : float
          Length of vector
  
      Returns
      -------
      list of (int, number)
          L2-normalized vector in BoW format.
  
      """
      if length != 1.0:
          return [(termid, val / length) for termid, val in vec]
      else:
          return list(vec)
  
imports: from __future__ import with_statement
  import logging
  import math
  from gensim import utils
  import numpy
  import scipy.sparse
  from scipy.stats import entropy
  from scipy.linalg import get_blas_funcs, triu
  from scipy.linalg.lapack import get_lapack_funcs
  from scipy.special import psi
label_desc: Use image node_id 15 for calling a global function with example usage: ret_normalized_vec(vec, length) and returns: unknown, list