Since there is no main() function in Python, when the command to run a python program is given to the interpreter, the code that is at level 0 indentation is to be executed. However, before doing that, it will define a few special variables. __name__ is one such special variable. If the source file is executed as the main program, the interpreter sets the __name__ variable to have a value “__main__”. If this file is being imported from another module, __name__ will be set to the module’s name.
__name__ is a built-in variable which evaluates to the name of the current module. Thus it can be used to check whether the current script is being run on its own or being imported somewhere else by combining it with if statement, as shown below.

In Python, __name__ is a special variable that is used to determine whether a module is being run as the main program or if it is being imported as a module by another program. It is a built-in variable in Python, and its value depends on how the code is being executed.

When a Python script is run, the interpreter sets the __name__ variable to "__main__", indicating that the script is being run as the main program. This allows you to include code that will only be executed if the script is run directly, rather than being imported as a module. For example, you might include test code or example usage code at the bottom of a script.

On the other hand, if a Python script is imported as a module by another program, the interpreter sets the __name__ variable to the name of the module. This allows you to define code that can be reused in other programs without executing the test or example code. For example, you might define functions, classes or constants that can be used in other programs.

To summarize, the __name__ variable is a useful way to distinguish between the main program and modules being imported, and it can be used to include or exclude certain blocks of code depending on how the code is being run.