Limit explanation to current function

Make it clear that we only have to define the given function before we call it, to avoid making readers think they might have to define all functions before any are called

Co-Authored-By: Raphael Das Gupta <raphael.das.gupta@hsr.ch>

Author: lindboe

en/python_introduction/README.md

@@ -815,7 +815,7 @@ hi()
 
 Okay, our first function is ready!
 
-You may wonder why we've written the name of the function at the bottom of the file. When we write `def hi():` and the indented lines following, this is us writing instructions for what the `hi()` function should do. Python will read and remember these instructions, but won't run the function yet. To tell Python we want to run the function, we have to call the function with `hi()`. Python reads the file and executes it from top to bottom, so we have to define functions in the file before we call them.
+You may wonder why we've written the name of the function at the bottom of the file. When we write `def hi():` and the indented lines following, this is us writing instructions for what the `hi()` function should do. Python will read and remember these instructions, but won't run the function yet. To tell Python we want to run the function, we have to call the function with `hi()`. Python reads the file and executes it from top to bottom, so we have to define the function in the file before we call it.
 
 Let's run this now and see what happens: