Building a python class step by step via patching

patch.py

class Snail:
  def __init__(self):
    self.speed = 0.001
    self.pos = 0
  
  def move(self):
    self.pos += self.speed
    print(f'moved to {self.pos}')
    
garry = Snail()
garry.move()
garry.move()

# let's add the abilty to move fast to the Snail class
from fastcore.basics import patch

@patch
def move_fast(self:Snail): # the type hint Snail is important, that's how patch knows which class to add the method do
    self.pos += (5 * self.speed)
    print(f'moved to {self.pos}')

garry = Snail()
garry.move_fast()
garry.move_fast()