understaning "self"

[Poppy]

I've been searching online to try get a better understanding of what "self" 
does when I define this parameter in my class functions. All I'm finding is 
debates on whether  "self" has any value to the language but that doesn't 
help me in my newbie question. So the code excerpt below is from "Beginning 
Python" Norton, Samuel, Aitel, Foster-Johnson, Richardson, Diamon, Parker, 
and Roberts.

What I think "self" is doing is limiting the function call to only function 
in "this" class. So in the function below "has" calls self.has_various(), if 
I had a function called "has_various" in my program or another included 
class using "self" insures that the "has_various" below is the one used. Am 
I correct in my understanding?

thanks,

Zach-




    def has(self, food_name, quantity=1):
        """
has(food_name, [quantity]) - checks if the string food_name is in the
fridge. quantity defaults to 1
returns True if there is enough, false otherwise.
"""

        return self.has_various({food_name:quantity})

    def has_various(self, foods):
        """
has various(foods) determines if the dictionary food_name
has enough of every element to satisfy a request.
returns true if there's enough, Fasle if there's not or if an element does
not exist.
"""
        try:
            for food in foods.keys():
                if self.items[food] < foods[food]:
                    return False
            return True
        except KeyError:
            return False