if __name__ == '__main__':

This line of code is often used in Python scripts and modules to determine if the code is being run as the main program or if it is being imported as a module into another program.

When a Python file is imported as a module into another program, any code outside of a function or class definition will be executed. This can cause issues if the code is not intended to be run when the file is imported.

By using the if __name__ == '__main__': statement, code can be placed inside this block that will only execute if the file is being run as the main program. This allows for separation of code that is meant to be run as a standalone program versus code that is meant to be used as a module.

For example:

def my_function():
    print('Hello, world!')

if __name__ == '__main__':
    my_function()

In this example, the function `my_function()` is defined outside of the if statement. However, when the code is run, the function will only be called if the file is being run as the main program. If the file is imported as a module, the function will not be called.