code: def _exact_1_norm(A):
      # A compatibility function which should eventually disappear.
      if scipy.sparse.isspmatrix(A):
          return max(abs(A).sum(axis=0).flat)
      else:
          return np.linalg.norm(A, 1)
  
imports: from __future__ import division, print_function, absolute_import
  import numpy
  import scipy.linalg
  import scipy.sparse.linalg
  from scipy.sparse.linalg import aslinearoperator
label_desc: Use image node_id 2 for calling a global function with example usage: _exact_1_norm(A) and returns: max, np