What is the ruling on the fast of one who fasted during her days of menstruation, believing that what was discharged was Istihadah (irregular vaginal bleeding outside of menstruation)?

The brown discharge connected to menstrual blood has the ruling of menses and is called "kudrah" (brownish discharge). "Kudrah" and "sufrah" (yellowish discharge) are considered menses during the time of menstruation, even if they do not appear with blood according to some jurists. There are two signs for the cessation of menstruation: "al-jufuf" (dryness, meaning the complete cessation of blood and any discharge connected to it) and "al-qassah al-bayda'" (a white discharge). If the questioner fasted days thinking she was pure while she was menstruating, or if she was unaware that fasting is impermissible during menstruation, then she must make up the fast of those days, as her fasting is not considered valid Islamically.