That's because function is not a python keyword.

If you expand your view just a little, you can see that function is a variable (passed in as a parameter).

def autoAddScript(function):
    """
        Returns a decorator function that will automatically add it's result to the element's script container.
    """
    def autoAdd(self, *args, **kwargs):
        result = function(self, *args, **kwargs)
        if isinstance(result, ClientSide.Script):
            self(result)
            return result
        else:
            return ClientSide.Script(ClientSide.var(result))
    return autoAdd

★[tex]\bf{\underline{Answer::}}[/tex]def is the keyword used to create a function in python.[tex]\rule{300pt}{0.2em}[/tex]★[tex]\bf{\underline{Example::}}[/tex]Let us take an example cοde to print "Hello World!" using a function:def my_func():   print("Hello World!")my_func()The output will be:Hello World!Explanation:    ❖ We define a function called my_func().    ❖ We define it to print the text Hello World!    ❖ Then we call the function and it prints the desired text onto the console.[tex]\rule{300pt}{0.2em}[/tex]★[tex]\bf{\underline{In-built \:functions\:in\:python::}}[/tex]    ✦ print() - Prints a value or a string to the console.    ✦ len() - Returns the length of an object (such as a string, list, or tuple).    ✦ type() - Returns the data type of an object.    ✦ str() - Converts an object into a string.    ✦ int() - Converts a string or a float into an integer.    ✦ float() - Converts a string or an integer into a float.    ✦ range() - Generates a sequence of numbers.    ✦ input() - Allows the user to input a value from the console.    ✦ max() - Returns the maximum value from a sequence.    ✦ min() - Returns the minimum value from a sequence.These are just a few functions. There are many more to explore![tex]\rule{300pt}{0.2em}[/tex]