In any language, if the program is getting bigger, you may have to split it into more files for easier maintenance. You may also want to use a function defined in a file without copying the entire logic in each file. To support this, Python has a way to put the definitions in a file and use them in a script wherever required to use those functions you have defined in that file. Such file is called as a module in Python. It always ends with .py extension.
You can call a function / definition defined in a module file using import statement in a script. For instance, I am defining a calc module with some definitions.
File: calc.py
