Create a class inheriting from Exception
:
class FooException(Exception):
pass
try:
raise FooException("insert description here")
except FooException:
print("A FooException was raised.")
or another exception type:
class NegativeError(ValueError):
pass
def foo(x):
# function that only accepts positive values of x
if x < 0:
raise NegativeError("Cannot process negative numbers")
... # rest of function body
try:
result = foo(int(input("Enter a positive integer: "))) # raw_input in Python 2.x
except NegativeError:
print("You entered a negative number!")
else:
print("The result was " + str(result))