Data analysis with python, function argument

Just a quick basic doubt, while using default arguments for functions like these:
def cost_calc(days,budget=1000):

When I call the function as cost_calc(10), it means we are giving days a value 0f 10 and the budget value is automatically assumed to be 1000 right?

But I’m getting an error. Please help me!

#THE ERROR

TypeError Traceback (most recent call last)
in
1 #1
2
----> 3 cost_calc(7)

TypeError: cost_calc() missing 1 required positional argument: ‘days’

Are you sure you defined the function correctly?