src/main/java/com/github/ricksbrown/cowsay/CowFace.java
public static final boolean isKnownMode(final String mode) {
		Set<String> modes = COW_MODES.keySet();
		return modes.contains(mode);
	}
public static final boolean isKnownMode(final String mode) {
		Set<String> modes = COW_MODES.keySet();
		return modes.contains(mode);
	}
Determine if the given mode flag is known and mapped to a particular cow face.
@param mode The key to the mode, generally a single character, e.g. "b" for "Borg" mode.
@return true if this is a known mode.