1class Material:
  2    density = 1
  3
  4    def __init__(self, weight):
  5        self.weight = weight
  6        self.is_valid = True
  7
  8    @property
  9    def volume(self):
 10        return self.weight / self.density
 11
 12
 13class Concrete(Material):
 14    density = 2500
 15
 16
 17class Brick(Material):
 18    density = 2000
 19
 20
 21class Stone(Material):
 22    density = 1600
 23
 24
 25class Wood(Material):
 26    density = 600
 27
 28
 29class Steel(Material):
 30    density = 7700
 31
 32existing_materials = {"Concrete": Concrete, "Brick": Brick, "Stone": Stone, "Wood": Wood, "Steel": Steel}
 33
 34
 35class Factory:
 36    created_factories = []
 37
 38    def __init__(self):
 39        self.created_materials = []
 40        Factory.created_factories.append(self)
 41
 42    def __call__(self, *args, **kwargs):
 43        if not args:
 44            if not kwargs:
 45                raise ValueError
 46            return self.__create_new_materials(kwargs)
 47        else:
 48            if kwargs:
 49                raise ValueError
 50            new_name, new_weight, new_density = self.__get_new_name_weight_density(args)
 51            return self.__create_and_add_material(new_name, new_weight, new_density)
 52
 53    def __create_and_add_material(self, name, weight, density):
 54        if name in existing_materials:
 55            new_material = existing_materials[name](weight)
 56            self.created_materials.append(new_material)
 57            return new_material
 58
 59        new_class = type(name, (Material,), {})
 60        new_class.density = density
 61        existing_materials[name] = new_class
 62
 63        new_material = existing_materials[name](weight)
 64        self.created_materials.append(new_material)
 65        return new_material
 66
 67    def __get_new_name_weight_density(self, args):
 68        weight_of_new_material = 0
 69        input_materials = []
 70        for material in args:
 71            if not material.is_valid:
 72                raise AssertionError
 73            material.is_valid = False
 74            input_materials.append(type(material).__name__)
 75            weight_of_new_material += material.weight
 76
 77        basic_materials = set()
 78
 79        for material in input_materials:
 80            basic_materials.update(material.split("_"))
 81        name_of_new_material = "_".join(sorted(basic_materials))
 82
 83        density_of_new_material = sum(existing_materials[str(material)].density for material in basic_materials)
 84        density_of_new_material /= len(basic_materials)
 85        return name_of_new_material, weight_of_new_material, density_of_new_material
 86
 87    def __create_new_materials(self, kwargs):
 88        result = []
 89        for material, weight in kwargs.items():
 90            if material not in existing_materials.keys():
 91                raise ValueError
 92            else:
 93                new_material = existing_materials[material](weight)
 94                self.created_materials.append(new_material)
 95                result.append(new_material)
 96        return tuple(result)
 97
 98    def can_build(self, wall_volume):
 99        return wall_volume <= self.__get_factory_volume()
100
101    def __get_factory_volume(self):
102        return sum(material.volume for material in self.created_materials if material.is_valid)
103
104    @classmethod
105    def can_build_together(cls, wall_volume):
106        factory_volume_together = sum(factory.__get_factory_volume() for factory in cls.created_factories)
107        return wall_volume <= factory_volume_together