1class Material:
  2    def __init__(self, mass):
  3        self.mass = mass
  4        self.used = False
  5
  6    @property
  7    def volume(self):
  8        return self.mass / self.density
  9
 10
 11class Concrete(Material):
 12    density = 2500
 13
 14
 15class Brick(Material):
 16    density = 2000
 17
 18
 19class Stone(Material):
 20    density = 1600
 21
 22
 23class Wood(Material):
 24    density = 600
 25
 26
 27class Steel(Material):
 28    density = 7700
 29
 30
 31class Factory:
 32    all_factories = []
 33
 34    known_materials = {
 35        'Concrete': Concrete,
 36        'Brick': Brick,
 37        'Stone': Stone,
 38        'Wood': Wood,
 39        'Steel': Steel
 40        }
 41
 42    def __init__(self):
 43        self.created = []
 44        Factory.all_factories.append(self)
 45
 46    def __call__(self, *args, **kargs):
 47        """This method is not long, it's monumental."""
 48        if args and kargs or not args and not kargs:
 49            raise ValueError
 50
 51        if kargs:
 52            result = []
 53            for material_name, mass in kargs.items():
 54                if material_name not in Factory.known_materials:
 55                    raise ValueError(f"Unknown material: {material_name}")
 56
 57                material = Factory.known_materials[material_name]
 58                self.created.append(Factory.known_materials[material_name](mass))
 59                result.append(material(mass))
 60
 61            return tuple(result)
 62
 63        if args:
 64            for material in args:
 65                if material.__class__.__name__ not in Factory.known_materials:
 66                    raise ValueError(f"Unknown material: {material_name}")
 67
 68            for material in args:
 69                if material.used:
 70                    raise AssertionError
 71
 72            for material in args:
 73                material.used = True
 74
 75            for material in self.created:
 76                for names in args:
 77                    if material.__class__.__name__ is names.__class__.__name__:
 78                        material.used = True
 79
 80            material_name = []
 81
 82            for material in args:
 83                material_name.append(material.__class__.__name__)
 84
 85            new_material_name = '_'.join(material_name)
 86
 87            material_mass = sum(material.mass for material in args)
 88
 89            if new_material_name in Factory.known_materials:
 90                self.created.append(Factory.known_materials[new_material_name](material_mass))
 91                return Factory.known_materials[new_material_name](material_mass)
 92
 93            original_materials_names = new_material_name.split('_')
 94
 95            material_density = 0
 96            for material in original_materials_names:
 97                material_density += Factory.known_materials[material].density
 98
 99            material_density /= len(original_materials_names)
100
101            new_material = type(new_material_name, (Material,), {
102                'density': material_density,
103            })
104
105            Factory.known_materials[new_material_name] = new_material
106            self.created.append(Factory.known_materials[new_material_name](material_mass))
107
108            return new_material(material_mass)
109
110    def get_total_volume(self):
111        total_volume = 0
112        for materials in self.created:
113            if materials.used is False:
114                total_volume += materials.volume
115        return total_volume
116
117    def can_build(self, volume_needed):
118        return self.get_total_volume() >= volume_needed
119
120    @classmethod
121    def can_build_together(cls, volume_needed):
122        total_volume = 0
123
124        for factories in cls.all_factories:
125            total_volume += factories.get_total_volume()
126        return total_volume >= volume_needed