| Functions returning some value are called as fruitful functions. | Functions that does not return any value are called as non-fruitful functions. |
| They are also called as non-void functions. | They are also called as void functions. |
They have return statements in the syntax : return<value>. | They may or may not have a return statement, but if they do, it typically appears as per syntax : return. |
| Fruitful functions return some computed result in terms of a value. | Non-fruitful functions return legal empty value of Python, which is None, to their caller. |