code: def test_math():
      """Math"""
  
      class Sigmoid(flow.nn.Module):
          def forward(self, x):
              return flow.sigmoid(x)
  
      class Sign(flow.nn.Module):
          def forward(self, x):
              return flow.sign(x)
  
      class Reciprocal(flow.nn.Module):
          def forward(self, x):
              return flow.reciprocal(x)
  
      class Pow(flow.nn.Module):
          def forward(self, x):
              return flow.pow(x, 2.0)
  
      class Log(flow.nn.Module):
          def forward(self, x):
              return flow.log(x)
  
      class Log2(flow.nn.Module):
          def forward(self, x):
              return flow.log1p(x)
  
      class Exp(flow.nn.Module):
          def forward(self, x):
              return flow.exp(x)
  
      class Exp2(flow.nn.Module):
          def forward(self, x):
              return flow.expm1(x)
  
      class Variance(flow.nn.Module):
          def forward(self, x):
              return flow.var(x, 1, unbiased=False, keepdim=True)
  
      model1 = Sigmoid().eval()
      model2 = Sign().eval()
      model3 = Log().eval()
      model4 = Log2().eval()
      model5 = Exp().eval()
      model6 = Exp2().eval()
      model7 = Reciprocal().eval()
      model8 = Pow().eval()
      model9 = Variance().eval()
  
      for device in ["llvm"]:
          verify_math(model1, device=device)
          verify_math(model2, device=device)
          verify_math(model3, device=device)
          verify_math(model4, device=device)
          verify_math(model5, device=device)
          verify_math(model6, device=device)
          verify_math(model7, device=device)
          verify_math(model8, device=device)
          verify_math(model9, device=device)
  
imports: import os
  import numpy
  import oneflow
  from packaging import version
  import tvm
  import tvm.testing
  import tvm.topi.testing
  from tvm import relay
label_desc: Use image node_id 25 for calling a global function with example usage: test_math() and returns: flow, flow, flow, flow, flow, flow, flow, flow, flow