Return true if the specified specChar represents a valid description of the expected result, and false otherwise. specChar is valid if it is either an (UPPERCASE) P (for Pass) or F (for Fail). Note that P is intended to represent the expectation that the function under test will "pass" by satisfying all preconditions, including the specific one guarded by the assertion under test, while an F is intended to indicate the expectation that the specific assertion under test will "fail" (thereby triggering a call to the currently‐installed assertion‐failure handler).