1class Material:
 2    density: float
 3    def __init__(self, mass):
 4        self.mass = mass
 5        self.volume = float(mass / self.density)
 6        self.valid = True
 7
 8
 9    
10class Concrete(Material):
11    density = 2500
12
13class Brick(Material):
14    density = 2000
15    
16class Stone(Material):
17    density = 1600
18  
19class Wood(Material):
20    density = 600
21  
22class Steel(Material):
23    density = 7700
24
25material_classes={"Concrete": Concrete, "Brick": Brick, "Stone": Stone, "Wood": Wood, "Steel": Steel}
26
27class Factory:
28    _total_volume = 0.0
29
30    def __init__(self):
31        self.volume = 0.0
32    
33    def __create_materials(self, kwds):
34        try:
35            materials = [material_classes[name](val) for name, val in kwds.items()]
36            if not all(isinstance(obj, Material) for obj in materials):
37                raise ValueError("Factory instance cannot be called with parameter names which are not materials!")
38            self.volume += sum([material.volume for material in materials])
39            type(self)._total_volume += sum([material.volume for material in materials])
40            return tuple(materials)
41        except:
42            raise ValueError("Factory instance cannot be called with parameter names which are not materials!")
43    
44    def __make_alloy(self, result_class, result_mass, volume_to_erase):
45        result_material = material_classes[result_class](result_mass)
46        self.volume -= volume_to_erase
47        self.volume += result_material.volume
48        type(self)._total_volume -= volume_to_erase
49        type(self)._total_volume += result_material.volume
50        return result_material
51    
52    def __create_new_material(self, args):
53        if any(not material.valid for material in args):
54            raise AssertionError("Factory instance cannot take already used materials!")
55        for material in args:
56            material.valid = False
57        volume_to_erase = sum([material.volume for material in args])
58        arg_material_names = [material.__class__.__name__ for material in args]
59        arg_material_names = [material for combination in arg_material_names for material in combination.split("_")]
60        arg_material_names.sort()
61        result_class = "_".join(arg_material_names)
62        result_mass = sum([material.mass for material in args ])
63        try:
64            return self.__make_alloy(result_class, result_mass, volume_to_erase)
65        except:
66            new_density: float =  sum(material_classes[material].density for material in arg_material_names) / len(arg_material_names)
67            material_classes[result_class] = type(result_class,(Material, ),{'density': new_density,})
68            return self.__make_alloy(result_class, result_mass, volume_to_erase)
69
70    def __call__(self, *args, **kwds):
71        if not args and not kwds:
72            raise ValueError("Factory instance cannot be called without parameters!")
73        if args and kwds:
74            raise ValueError("Factory instance cannot be called with both positional and named parameters!")
75        if kwds:
76            return self.__create_materials(kwds)
77        if args:
78            return self.__create_new_material(args)
79    
80    def can_build(self, required_volume):
81        return self.volume >= required_volume
82    
83    @classmethod
84    def can_build_together(cls, required_volume):
85        return cls._total_volume >= required_volume
86