Object-oriented model for a calorie counter sporting polymorphic methods for both genders.

Concerns:

• BPM curve for exercise acts of longer duration: can this be added without being too invasive?
• Side-effect or coupling between main and the read_person_attributes function through the del statement which modifies the argument: is this a necessary evil, or can it be removed?

from abc import ABC, abstractmethod   def main():     person_attributes = read_person_attributes()     person = PersonFactory.make_person(person_attributes)      print("You've burned approximately {0} calories.".format(round(person.calories_burned, 1)))   def read_person_attributes():     """Prompts a user for their details     """     person_attributes = {         'gender': input('Your gender (male, female): '),         'weight_kg': int(input('Your weight in kg: ')),         'age': int(input('Your age: ')),         'bpm': int(input('Your heart rate in bpm: ')),         'exercise_duration_min': int(input('Your exercise duration in minutes: '))     }      return person_attributes  class Person(ABC):     def __init__(self, weight_kg, bpm, age, exercise_duration_min):         self.weight_kg = weight_kg         self.age = age         self.bpm = bpm         self.exercise_duration_min = exercise_duration_min      @property     @abstractmethod     def calories_burned(self):         raise NotImplementedError   class Male(Person):     @property     def calories_burned(self):         return ((self.age * 0.2017) - (self.weight_kg * 0.09036) + (self.bpm * 0.6309) - 55.0969) * self.exercise_duration_min / 4.184   class Female(Person):     @property     def calories_burned(self):         return ((self.age * 0.074) - (self.weight_kg * 0.05741) + (self.bpm * 0.4472) - 20.4022) * self.exercise_duration_min / 4.184   class PersonFactory:     @staticmethod     def make_person(person_attributes):         """         Instantiate a person of the proper gender based on the provided attributes.         Args:             person_attributes: A dictionary containing the keys:             ('gender', 'age, 'weight_kg', exercise_duration_min, bpm)         """         gender = person_attributes['gender'].lower()         del person_attributes['gender']          if gender == 'male':             return Male(**person_attributes)         elif gender == 'female':             return Female(**person_attributes)         else:             raise RuntimeError('Invalid gender')   if __name__ == '__main__':     main()