code: def if_present(f):
      return lambda o: f(o) if o is not None else None
  
file_path: sonnet/sonnet/src/conformance/build_test.py
imports: from absl.testing import parameterized
  import sonnet
  from sonnet.src import test_utils
  from sonnet.src.conformance import descriptors
  import tensorflow
  import tree
label_desc: Use image node_id 1 for calling a global function with example usage: if_present(f) and returns: function