class NegativeNumberError(Exception):
    pass

def check_number(n):
    if n < 0:
        raise NegativeNumberError("Negative numbers are not allowed")

check_number(-3)

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NegativeNumberError                       Traceback (most recent call last)

Cell In[1], line 8
      5     if n < 0:
      6         raise NegativeNumberError("Negative numbers are not allowed")
----> 8 check_number(-3)


Cell In[1], line 6, in check_number(n)
      4 def check_number(n):
      5     if n < 0:
----> 6         raise NegativeNumberError("Negative numbers are not allowed")


NegativeNumberError: Negative numbers are not allowed