how to make an error message in python code example

Example 1: raise python

# Raise is used to cause an error
raise(Exception("Put whatever you want here!"))
raise(TypeError)

Example 2: except as Exception:

>>> def catch():
...     try:
...         asd()
...     except Exception as e:
...         print e.message, e.args
... 
>>> catch()
global name 'asd' is not defined ("global name 'asd' is not defined",)

Example 3: python exception

try:
  # code block
except ValueError as ve:
  print(ve)