Fix typing for Python <3.7

Fix a runtime issue with ACTS running on versions of Python less than
3.7. Remove specific subclasses from the Union since this was a specific
feature added in Python 3.7.

Bug: None
Test: act.py [...] -tc Sl4fSanityTest
Change-Id: Ia2778ce8d3ee60647652b41eca4341231e98d56d
1 file changed
tree: c3ef571ad59d6dc02985b03830a1d6d9c7a0e3fe
  1. acts/
  2. acts_tests/
  3. tools/
  4. wts-acts/
  5. Android.mk
  6. LICENSE
  7. OWNERS
  8. PREUPLOAD.cfg