How to resolve NameError: name ‘mystring’ is not defined error in python ?

I got below error message when executing my python script.

user@ngelinux$ ./fourth.py 
5
5.199
Traceback (most recent call last):
  File "./fourth.py", line 13, in 
    print(mystring)
NameError: name 'mystring' is not defined
user@ngelinux$ 

Resolution
As the error says, the name “mystring” is not defined in the script.

Hence to resolve the issue define this variable in the script as follows:

### define the variable like below and print it.
mystring="new string var"

### Now the issue is resolved..
user@ngelinux$ 
user@ngelinux$ ./fourth.py 
5
5.199
hello
5.0
new string var
user@ngelinux$