Only run pytype on 2.7 and 3.7

PiperOrigin-RevId: 353259081
Change-Id: I410e5af3f280db6cb2780e2837977c725b21bb0f

Author: dbieber

.travis.yml

@@ -19,8 +19,8 @@ script:
   - pip install ipython
   - python -m pytest  # Now run the tests with IPython.
   - pylint fire --ignore=test_components_py3.py,parser_fuzz_test.py,console
-  - if [[ $TRAVIS_PYTHON_VERSION != 3.4 && \
-          $TRAVIS_PYTHON_VERSION != 3.5 ]]; then
+  - if [[ $TRAVIS_PYTHON_VERSION == 2.7 || \
+          $TRAVIS_PYTHON_VERSION == 3.7 ]]; then
       pip install pytype;
     fi
   # Run type-checking, excluding files that define or use py3 features in py2.
@@ -29,8 +29,6 @@ script:
         fire/fire_test.py
         fire/inspectutils_test.py
         fire/test_components_py3.py;
-    elif [[ $TRAVIS_PYTHON_VERSION != 3.4 && \
-            $TRAVIS_PYTHON_VERSION != 3.5 && \
-            $TRAVIS_PYTHON_VERSION != 3.9 ]]; then
+    elif [[ $TRAVIS_PYTHON_VERSION == 3.7 ]]; then
       pytype;
     fi