raise NotImplementedError to indicate abstract methods._ in their name, e.g. _secret1_000_000 over 1000000._ for unused variables: _, extension = 'foobar.txt'.split('.')Volt = floatwith open('file.txt', 'r') as f:for car in cars:for idx, car in enumerate(cars):for car, driver in zip(cars, drivers):Example
class Employee(Person):           # inheritance
  count = 0                       # static attr. (shared by all instances)
  def __init__(self, name: str):  # constructor
     super().__init__()
     Employee.count += 1
     self.name = name             # local attr. (local to one instance)
  
     print(Employee.count)