Plan

# We will assume that when we begin running the program there are no inventories of bikes. Bikes can be created by our program. 
# Each bike has a unique serial. The type of bike is determined by: model, size and color. 
# Considering the usage, users might want to find data by serial number, or buy a bike according to it's type. 

# Company. I can create a company class. Due to the scope of this project I will not create a company class, but simply assume 1 company. 
# Data to update: new models, change in cost or weight of a certain model . 
model dictionary = {model:[catagory, description]   .....}
type dictionary = {[model ,size]:[weight, cost]   ......}
optional colors = {'Red', 'Blue', 'Green', 'Yellow'}
#Constant data
optional size = {'Small', 'Medium', 'Large', 'ExtraLarge'}
# Database - should we prepare a seperate database for company, shops and users, or a centralized one? In this case a seperate one.  
companysInventory = {serial:[model, size, color, weight, cost]    ......}
#The company has two basic functions. The first is creating a bike. That will be done when a bicycle object is being initialized. The second function is selling a bike. This will be done by the sellRequest function.
function sellRequest (model, size, color):
    look for requested bike in inventory. if exist: 1)return to shop approval, and details of bike, 2) reduce bike from inventory. if not, return refusal and send inventory.

# Bicycle
count = 0
class Bicycle ():
    def __init__ (self, modelName, size, color):
        self.serial = count
        count ++ 
        # modelName, size and color can only be of a certain kind, mentioned in company's database.  
        if modelName in model dictionary: 
            self.modelName = modelName
        else: provide model list and request user to chose. 
        #same proceedure with size and color. 
        self.size = size
        self.color = color
        add entry to inventory
        
class Shop ():    
    sellMargin=0.2
    inventory = {serial:[model, size, color, weight, cost]    ......}
    def __init__ (self, name):
        self.name =name
    def buyBike (self, modelName, size, color):
        #We will request sell from company
        sellRequest(modelName, size, color)
        if approved add bike to inventory
        if not present to user companys inventory and allow user to choose a different bike. 
        call sellRequest fun again with the new requested bike. 
    profitPerModelDic = {model:profit .......}  
    function sellRequest (model, size, color):
    look for requested bike in inventory. if exist: 1)return to customer approval, and details of bike, 2) reduce bike from inventory, and update profit dictionary. if not, return refusal and send inventory.
        
    
class Customer ():
        def __init__ (self, name, fund):
        self.name = name
        self.fund = fund
        own = {}
        def buy (modelName, size, color):
            #We will request sell from shop
            shop.sellRequest (modelName, size, color)
            if not present to user shop's inventory and allow user to choose a different bike. 
            call sellRequest fun again with the new requested bike.