# exceptions/replace.py
# This is not a valid Python module - Don't run it.
>>> class NotFoundError(Exception):
...     pass
...
>>> vowels = {'a': 1, 'e': 5, 'i': 9, 'o': 15, 'u': 21}
>>> try:
...     pos = vowels['y']
... except KeyError as e:
...     raise NotFoundError(*e.args)
...
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
KeyError: 'y'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 4, in <module>
__main__.NotFoundError: y
>>> try:
...     pos = vowels['y']
... except KeyError as e:
...     raise NotFoundError(*e.args) from e
...
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
KeyError: 'y'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<stdin>", line 4, in <module>
__main__.NotFoundError: y