code: public static final boolean isKnownMode(final String mode) {
  		Set<String> modes = COW_MODES.keySet();
  		return modes.contains(mode);
  	}
docs: 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.