code: def test_is_sorted():
      u_src, u_dst = edge_pair_input(False)
      s_src, s_dst = edge_pair_input(True)
  
      u_src = F.tensor(u_src, dtype=F.int32)
      u_dst = F.tensor(u_dst, dtype=F.int32)
      s_src = F.tensor(s_src, dtype=F.int32)
      s_dst = F.tensor(s_dst, dtype=F.int32)
  
      src_sorted, dst_sorted = dgl.utils.is_sorted_srcdst(u_src, u_dst)
      assert src_sorted == False
      assert dst_sorted == False
  
      src_sorted, dst_sorted = dgl.utils.is_sorted_srcdst(s_src, s_dst)
      assert src_sorted == True
      assert dst_sorted == True
  
      src_sorted, dst_sorted = dgl.utils.is_sorted_srcdst(u_src, u_dst)
      assert src_sorted == False
      assert dst_sorted == False
  
      src_sorted, dst_sorted = dgl.utils.is_sorted_srcdst(s_src, u_dst)
      assert src_sorted == True
      assert dst_sorted == False
  
imports: import math
  import numbers
  import backend
  import dgl
  import networkx
  import numpy
  import pytest
  import scipy.sparse
  from dgl import DGLError
label_desc: Use image node_id 15 for calling a global function with example usage: test_is_sorted() without return types