code: public static Strictness determineStrictness(Stubbing stubbing, MockCreationSettings mockSettings, Strictness testLevelStrictness) {
          if (stubbing != null && stubbing.getStrictness() != null) {
              return stubbing.getStrictness();
          }
  
          if (mockSettings.isLenient()) {
              return Strictness.LENIENT;
          }
  
          return testLevelStrictness;
      }
docs: Determines the actual strictness in the following importance order:
  1st - strictness configured when declaring stubbing;
  2nd - strictness configured at mock level;
  3rd - strictness configured at test level (rule, mockito session)
  
  @param stubbing stubbing to check for strictness. Null permitted.
  @param mockSettings settings of the mock object, may or may not have strictness configured. Must not be null.
  @param testLevelStrictness strictness configured using the test-level configuration (rule, mockito session). Null permitted.
  
  @return actual strictness, can be null.