if __name__ == "__main__"

This is a Python syntax that is commonly used to check whether the current module is being run as the main program or if it is being imported as a module into another program.

When a Python module is imported into another program, the code in the module is executed. However, there may be some code in the module that should only be executed if the module is being run as the main program.

For example, consider a module that defines a function to print "Hello, World!". If this module is imported into another program, the function will be defined but not executed. However, if the module is run as the main program, the function will be executed and "Hello, World!" will be printed to the console.

The `if __name__ == "__main__":` statement is used to define code that should only be executed when the module is run as the main program. Any code outside of this statement will be executed whenever the module is imported into another program.

Here's an example:

def hello_world():
    print("Hello, World!")

if __name__ == "__main__":
    hello_world()

In this example, the `hello_world()` function is defined. The `if __name__ == "__main__":` statement checks whether the module is being run as the main program. If it is, the `hello_world()` function is executed and "Hello, World!" is printed to the console. If the module is imported into another program, the `hello_world()` function will be defined but not executed.