human
Solve in Python:
Your task in this kata is to implement the function `create_number_class` which will take a string parameter `alphabet` and return a class representing a number composed of this alphabet.

The class number will implement the four classical arithmetic operations (`+`, `-`, `*`, `//`), a method to convert itself to string, and a `convert_to` method which will take another class number as parameter and will return the value of the actual class number converted to the equivalent value with tha alphabet of the parameter class (return a new instance of this one).

Example:

```python
BinClass = create_number_class('01')
HexClass = create_number_class('0123456789ABCDEF')

x = BinClass('1010')
y = BinClass('10')

print(x+y)                   => '1100'
isinstance(x+y, BinClass)    => True
print(x.convert_to(HexClass) => 'A'
```

___Notes:___

* Only positives integers will be used (either as parameters or results of calculations).
* You'll never encounter invalid calculations (divisions by zero or things like that).
* Alphabets will contain at least 2 characters.
assistant
#Here is the Python code you requested.

def create_number_class(alphabet):
    jinwei = len(alphabet)
    def str2dec(string : str) -> int:
        dec, base = 0, 1
        for dig in reversed(string):
            dec += base * alphabet.index(dig)
            base *= jinwei
        return dec
    def dec2str(dec : int) -> str:
        string = ''
        while 1:
            string += alphabet[dec % jinwei]
            dec = dec // jinwei
            if 0 is dec: return string[::-1]
    class number:
        def __init__(self, str_or_dec):
            if isinstance(str_or_dec, str):
                self.str = str_or_dec
                self.dec = str2dec(self.str)
            else:
                self.dec = str_or_dec
                self.str = dec2str(self.dec)
        def convert_to(self, _class):
            return _class(self.dec)
        def __str__(self):
            return self.str
        def __add__(self, x):
            return number(self.dec + x.dec)
        def __sub__(self, x):
            return number(self.dec - x.dec)
        def __mul__(self, x):
            return number(self.dec * x.dec)
        def __floordiv__(self, x):
            return number(self.dec // x.dec)
    return number