Multiple setInsensitiveRange

i need to keep selectable for a month only days 1st,15th and the last.
using setInsensitiveRange if i try to add the second Range the first is overwrite.

myCalendar1.setInsensitiveRange("2019-01-01", "2019-01-15")
myCalendar1.setSensitiveRange("2019-01-16", "2019-01-31")

is there any trick?

i tried to use disableDays, but calndar is some cases shows previous dates