__init__.py

# File deliberately empty, but gist won't allow it

example.py

import random
import uuid

import datetime as dt

SOME_VARIABLE = 2


class Job:

    def __init__(
        self,
        service_id: str,
        start_time: int,
        end_time: int,
        duration: int,
        _id: str = uuid.uuid4().hex
    ):
        
        self.service_id = service_id
        self.start_time = start_time
        self.end_time = end_time
        self.duration = duration
        self._id = _id # Attributes with leading _ are "private"
        
    def get_human_timeslot(self):
        start_hours = self.start_time // 60
        start_mins = self.start_time - (start_hours * 60)
        end_hours = self.end_time // 60
        end_mins = self.end_time - (end_hours * 60)
        print((
            dt.datetime(1900, 1, 1, start_hours, start_mins)).strftime("%H:%M"),
            '-',
            dt.datetime(1900, 1, 1, end_hours, end_mins).strftime("%H:%M")
        )
        

class Delivery(Job):
    
    def __init__(
        self,
        capacity: int,
        **kwargs,
        
    ):
        super().__init__(**kwargs)
        self.capacity = capacity
        

class Vehicle:
    
    def __init__(
        self,
        capacity: int = 10
    ):
        self.capacity = capacity


class Problem:
    
    def __init__(self):
        self._jobs = []
    
    def add_job(self, job):
        if not isinstance(job, Job):
            raise TypeError("Not a job!")
        self._jobs.append(job)
    
    def show_job_timeslots(self):
        if self._jobs:
            for item in self._jobs:
                item.get_human_timeslot()
        else:
            print("No jobs exist")
        
        
problem_a = Problem()
problem_b = Problem()

for x in range(5):
    start_time = random.randint(300, 1100)
    job = Job(
        service_id=str(random.randint(100, 999)), 
        start_time=start_time, 
        end_time=start_time + random.randint(0, 60),
        duration=random.randint(10, 30)
    )
    problem_a.add_job(job)
    
    delivery = Delivery(
        service_id=str(random.randint(100, 999)), 
        start_time=start_time, 
        end_time=start_time + random.randint(0, 60),
        duration=random.randint(10, 30), 
        capacity=random.randint(1, 15)
    )
    problem_a.add_job(delivery)

problem_a.show_job_timeslots()
print()

# This breaks the interface contract
# car_1 = Vehicle()
# problem_a.add_job(car_1)

# This is empty. We never added anything to this *instance* of Problem
problem_b.show_job_timeslots()

print("#############")

# Checking for instance hierarchy
a_job = Job(
    service_id=str(random.randint(100, 999)), 
    start_time=start_time, 
    end_time=start_time + random.randint(0, 60),
    duration=random.randint(10, 30)
)
a_delivery = Delivery(
    service_id=str(random.randint(100, 999)), 
    start_time=start_time, 
    end_time=start_time + random.randint(0, 60),
    duration=random.randint(10, 30), 
    capacity=random.randint(1, 15)
)

print(isinstance(a_job, Job))
print(isinstance(a_delivery, Job))
print(isinstance(a_job, Delivery))
    

example_2.py

from example import problem_a, Delivery, SOME_VARIABLE
# Try hashing out ALL of the code below and run this file. Note that you still
# get things printed out. That's because the act of importing a module will 
# also run its full contents! That's where `if __name__ == 'main__':` guard
# comes in


import random


start_time = random.randint(1, 40)
# This job will be in the evening, unlike all the others
new_job = Delivery(
            service_id=str(random.randint(100, 999)), 
            start_time=start_time, 
            end_time=start_time + random.randint(0, 60),
            duration=random.randint(10, 30), 
            capacity=random.randint(1, 15)
        )

problem_a.add_job(new_job)

problem_a.show_job_timeslots()

print(SOME_VARIABLE)