default argument value is mutable in mpl_map

[ReimarBauer]

Default argument values are evaluated only once, at function definition. Consequently, any modification to that value will affect all subsequent calls.

def set_draw_airports(self, value, port_type=["small_airport"], reload=True):
def set_draw_airspaces(self, value, airspaces=[], range_km=None, reload=True):
def draw_airspaces(self, countries=[], range_km=None):

a solution is to define it None and set the value because it is None.

e.g.

def set_draw_airports(self, value, port_type=None, reload=True):
    if port_type is None:
        port_type=["small_airport"]