So I was doing a little tutorial on inheritance in Python and created this class:

```
class Animal:
# variables with 2 underscores in front of them are private and can
# only be modified using functions inside the class
__name = ""
__height = 0
__weight = 0
__sound = ""

def __init__(self, name, height, weight, sound):
    self.__name = name
    self.__height = height
    self.__weight = weight
    self.__sound = sound

def setName(self, name):
    self.__name = name

def getName(self):
    return self.__name

def setHeight(self, height):
    self.__height = height

def getHeight(self):
    return self.__height

def setWeight(self, weight):
    self.__weight = weight

def getWeight(self):
    return self.__weight

def setSound(self, sound):
    self.__sound = sound

def getSound(self):
    return self.__sound

def getType(self):
    print("Animal")

def toString(self):
    print("{} is {} cm tall, weighs {} kilogram and says {}".format(self.__name,
                                                                    self.__height,
                                                                    self.__weight,
                                                                    self.__sound))

```

I then created an object:

```
cat = Animal("Charlie", 38, 12, "Meow")
print(cat.toString())

```

But when I run the program, the console tells me:

Charlie is 38 cm tall, weighs 12 kilogram and says Meow  

None

I'm trying to figure out why the "None" is there because it seems to be doing everything right, it's inputting all the values I give it. I'm very new to Python, hope someone can help.