> ## Documentation Index > Fetch the complete documentation index at: https://docs.ag2.ai/llms.txt > Use this file to discover all available pages before exploring further. # autogen.io.InputStream

`InputStream`



```python theme={null}
InputStream(*args, **kwargs)
```

Base class for protocol classes.
Protocol classes are defined as:: 
    class Proto(Protocol): 
        def meth(self) -> int: 
            ...
Such classes are primarily used with static type checkers that recognize
structural subtyping (static duck-typing).
For example:: 
    class C: 
        def meth(self) -> int: 
            return 0

def func(x: Proto) -> int: 
        return x.meth()

func(C())  # Passes static type check

See PEP 544 for details. Protocol classes decorated with
@typing.runtime\_checkable act as simple-minded runtime protocols that check
only the presence of given attributes, ignoring their type signatures.
Protocol classes can be generic, they are defined as:: 
    class GenProto[T](Protocol): 
        def meth(self) -> T: 
            ...

Parameters:

| Name       | Description |
| ---------- | ----------- |
| `*args`    |             |
| `**kwargs` |             |

### Instance Methods



#### input

```python theme={null}
input(
    self,
    prompt: str = '',
    *,
    password: bool = False
) -> str
```

Read a line from the input stream.


Parameters:

| Name       | Description                                                                                                       |
| ---------- | ----------------------------------------------------------------------------------------------------------------- |
| `prompt`   | The prompt to display.

Defaults to "".

**Type:** str

**Default:** ''             |
| `password` | Whether to read a password.

Defaults to False.

**Type:** bool

**Default:** False |

Returns:

| Type | Description                               |
| ---- | ----------------------------------------- |
| str  | str: The line read from the input stream. |