What is the typing.TypeVarTuple?

Question

Accepted Answer

**TypeVarTuple** allows **variadic generics** (variable number of type parameters).

```python
from typing import TypeVarTuple

Ts = TypeVarTuple("Ts")

# Variadic generic class
class Array(*tuple[Ts]):
    def __init__(self, *args: *Ts):
        self.data = args

# Type-safe usage
a: Array[int, str, float] = Array(1, "hello", 3.14)

# With TypeVar
from typing import TypeVar

T = TypeVar("T")

class Tuple(*tuple[T, *Ts]):
    pass

# In practice — used for typed *args
from typing import TypeVarTuple, Unpack

Ts = TypeVarTuple("Ts")

def merge(*args: *Ts) -> tuple[*Ts]:
    return args

result = merge(1, "hello", 3.14)  # tuple[int, str, float]
```

**Benefits:**
- Typed variadic functions.
- Better generic APIs.
- Type-safe *args.

Python: What is the typing.TypeVarTuple?