Dependency inversion

# line 6, CurrencyConverter is subclass of high-level AbatractBaseClass ABC  
# line 16, AlphaConverter is subclass of CurrencyConverter 
# line 32, App is dependent of above high-level class i.e. dependency inversion 
from abc import ABC

class CurrencyConverter(ABC):
    def convert(self, from_currency, to_currency, amount) -> float:
        pass

class FXConverter(CurrencyConverter):
    def convert(self, from_currency, to_currency, amount) -> float:
        print('Converting currency using FX API')
        print(f'{amount} {from_currency} = {amount * 1.2} {to_currency}')
        return amount * 1.15

class AlphaConverter(CurrencyConverter):
    def convert(self, from_currency, to_currency, amount) -> float:
        print('Converting currency using Alpha API')
        print(f'{amount} {from_currency} = {amount * 1.2} {to_currency}')
        return amount * 1.2

class App:
    def __init__(self, converter: CurrencyConverter):
        self.converter = converter

    def start(self):
        self.converter.convert('EUR', 'USD', 100)


if __name__ == '__main__':
    converter = AlphaConverter()
    app = App(converter)
    app.start()
# output    
# Converting currency using Alpha API
# 100 EUR = 120.0 USD

Source: pythontutorial.net

Similar codes

0 vote349 views1 answer
Python sleeping with a varible
Python
0 vote373 views6 answers
Virtualenv
Python
2 votes341 views2 answers
How to send a message from google form to a python
Python
5 votes334 views1 answer
How to unzip files using zipfile module python
Python
11 votes352 views3 answers
Reorder columns in python
Python
5 votes340 views2 answers
Jupyter nbextension
Python
0 vote332 views2 answers
Pywavelets tutorial
Python
1 vote349 views1 answer
Easiest way to position labels in tkinter
Python
1 vote345 views1 answer
Unique words from pandas
Python
0 vote357 views1 answer
Os.name == 'nt'
Python