code: def elsym(edgelen, order=1):
      """
      Elementary symmetric polynomial of a given order
      """
      l = len(edgelen)
      if order == 0:
          return 1
      r = 0
      for v in combinations(range(l), order):
          r += np.prod([edgelen[vv] for vv in v])
      return r
  
imports: from itertools import combinations
  import numpy
  import numpy.linalg
  import pytest
  from numpy.testing import assert_almost_equal, assert_array_equal
  from ..None import intvol
label_desc: Use image node_id 5 for calling a global function with example usage: elsym(edgelen, order) and returns: r, int