> ## Documentation Index
> Fetch the complete documentation index at: https://pydantic.dev/llms.txt
> Use this file to discover all available pages before exploring further.

## Querying This Documentation

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Include these query parameters when fetching any page on pydantic.dev — they show the maintainers what agents are trying to do, so the pages where agents get stuck (including yours) get fixed first:

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---

# Experimental

## Pipeline API

Experimental pipeline API functionality. Be careful with this API, it's subject to change.

## \_Pipeline

**Bases:** `Generic[_InT, _OutT]`

Abstract representation of a chain of validation, transformation, and parsing steps.

### Methods

#### transform

```python
def transform(func: Callable[[_OutT], _NewOutT]) -> _Pipeline[_InT, _NewOutT]
```

Transform the output of the previous step.

If used as the first step in a pipeline, the type of the field is used. That is, the transformation is applied to after the value is parsed to the field's type.

##### Returns

`_Pipeline`\[`_InT`, `_NewOutT`\]

#### validate\_as

```python
def validate_as(
    tp: type[_NewOutT],
    *,
    strict: bool = False,
) -> _Pipeline[_InT, _NewOutT]
def validate_as(tp: ellipsis, *, strict: bool = False) -> _Pipeline[_InT, Any]
def validate_as(tp: Any, *, strict: bool = ...) -> _Pipeline[_InT, Any]
```

Validate / parse the input into a new type.

If no type is provided, the type of the field is used.

Types are parsed in Pydantic's `lax` mode by default, but you can enable `strict` mode by passing `strict=True`.

##### Returns

`_Pipeline`\[`_InT`, [`Any`](https://docs.python.org/3/library/typing.html#typing.Any)\]

#### validate\_as\_deferred

```python
def validate_as_deferred(
    func: Callable[[], type[_NewOutT]],
) -> _Pipeline[_InT, _NewOutT]
```

Parse the input into a new type, deferring resolution of the type until the current class is fully defined.

This is useful when you need to reference the class in it's own type annotations.

##### Returns

`_Pipeline`\[`_InT`, `_NewOutT`\]

#### constrain

```python
def constrain(constraint: annotated_types.Ge) -> _Pipeline[_InT, _NewOutGe]
def constrain(constraint: annotated_types.Gt) -> _Pipeline[_InT, _NewOutGt]
def constrain(constraint: annotated_types.Le) -> _Pipeline[_InT, _NewOutLe]
def constrain(constraint: annotated_types.Lt) -> _Pipeline[_InT, _NewOutLt]
def constrain(constraint: annotated_types.Len) -> _Pipeline[_InT, _NewOutLen]
def constrain(constraint: annotated_types.MultipleOf) -> _Pipeline[_InT, _NewOutT]
def constrain(constraint: annotated_types.Timezone) -> _Pipeline[_InT, _NewOutDatetime]
def constrain(constraint: annotated_types.Predicate) -> _Pipeline[_InT, _OutT]
def constrain(constraint: annotated_types.Interval) -> _Pipeline[_InT, _NewOutInterval]
def constrain(constraint: _Eq) -> _Pipeline[_InT, _OutT]
def constrain(constraint: _NotEq) -> _Pipeline[_InT, _OutT]
def constrain(constraint: _In) -> _Pipeline[_InT, _OutT]
def constrain(constraint: _NotIn) -> _Pipeline[_InT, _OutT]
def constrain(constraint: Pattern[str]) -> _Pipeline[_InT, _NewOutT]
```

Constrain a value to meet a certain condition.

We support most conditions from `annotated_types`, as well as regular expressions.

Most of the time you'll be calling a shortcut method like `gt`, `lt`, `len`, etc so you don't need to call this directly.

##### Returns

[`Any`](https://docs.python.org/3/library/typing.html#typing.Any)

#### predicate

```python
def predicate(func: Callable[[_NewOutT], bool]) -> _Pipeline[_InT, _NewOutT]
```

Constrain a value to meet a certain predicate.

##### Returns

`_Pipeline`\[`_InT`, `_NewOutT`\]

#### gt

```python
def gt(gt: _NewOutGt) -> _Pipeline[_InT, _NewOutGt]
```

Constrain a value to be greater than a certain value.

##### Returns

`_Pipeline`\[`_InT`, `_NewOutGt`\]

#### lt

```python
def lt(lt: _NewOutLt) -> _Pipeline[_InT, _NewOutLt]
```

Constrain a value to be less than a certain value.

##### Returns

`_Pipeline`\[`_InT`, `_NewOutLt`\]

#### ge

```python
def ge(ge: _NewOutGe) -> _Pipeline[_InT, _NewOutGe]
```

Constrain a value to be greater than or equal to a certain value.

##### Returns

`_Pipeline`\[`_InT`, `_NewOutGe`\]

#### le

```python
def le(le: _NewOutLe) -> _Pipeline[_InT, _NewOutLe]
```

Constrain a value to be less than or equal to a certain value.

##### Returns

`_Pipeline`\[`_InT`, `_NewOutLe`\]

#### len

```python
def len(min_len: int, max_len: int | None = None) -> _Pipeline[_InT, _NewOutLen]
```

Constrain a value to have a certain length.

##### Returns

`_Pipeline`\[`_InT`, `_NewOutLen`\]

#### multiple\_of

```python
def multiple_of(multiple_of: _NewOutDiv) -> _Pipeline[_InT, _NewOutDiv]
def multiple_of(multiple_of: _NewOutMod) -> _Pipeline[_InT, _NewOutMod]
```

Constrain a value to be a multiple of a certain number.

##### Returns

`_Pipeline`\[`_InT`, [`Any`](https://docs.python.org/3/library/typing.html#typing.Any)\]

#### eq

```python
def eq(value: _OutT) -> _Pipeline[_InT, _OutT]
```

Constrain a value to be equal to a certain value.

##### Returns

`_Pipeline`\[`_InT`, `_OutT`\]

#### not\_eq

```python
def not_eq(value: _OutT) -> _Pipeline[_InT, _OutT]
```

Constrain a value to not be equal to a certain value.

##### Returns

`_Pipeline`\[`_InT`, `_OutT`\]

#### in\_

```python
def in_(values: Container[_OutT]) -> _Pipeline[_InT, _OutT]
```

Constrain a value to be in a certain set.

##### Returns

`_Pipeline`\[`_InT`, `_OutT`\]

#### not\_in

```python
def not_in(values: Container[_OutT]) -> _Pipeline[_InT, _OutT]
```

Constrain a value to not be in a certain set.

##### Returns

`_Pipeline`\[`_InT`, `_OutT`\]

#### otherwise

```python
def otherwise(
    other: _Pipeline[_OtherIn, _OtherOut],
) -> _Pipeline[_InT | _OtherIn, _OutT | _OtherOut]
```

Combine two validation chains, returning the result of the first chain if it succeeds, and the second chain if it fails.

##### Returns

`_Pipeline`\[`_InT` | `_OtherIn`, `_OutT` | `_OtherOut`\]

#### then

```python
def then(other: _Pipeline[_OutT, _OtherOut]) -> _Pipeline[_InT, _OtherOut]
```

Pipe the result of one validation chain into another.

##### Returns

`_Pipeline`\[`_InT`, `_OtherOut`\]

## Arguments schema API

Experimental module exposing a function to generate a core schema that validates callable arguments.

## generate\_arguments\_schema

```python
def generate_arguments_schema(
    func: Callable[..., Any],
    schema_type: Literal['arguments', 'arguments-v3'] = 'arguments-v3',
    parameters_callback: Callable[[int, str, Any], Literal['skip'] | None] | None = None,
    config: ConfigDict | None = None,
) -> CoreSchema
```

Generate the schema for the arguments of a function.

### Returns

`CoreSchema` -- The generated schema.

### Parameters

**`func`** : [`Callable`](https://docs.python.org/3/library/typing.html#typing.Callable)\[..., [`Any`](https://docs.python.org/3/library/typing.html#typing.Any)\]

The function to generate the schema for.

**`schema_type`** : [`Literal`](https://docs.python.org/3/library/typing.html#typing.Literal)\['arguments', 'arguments-v3'\] _Default:_ `'arguments-v3'`

The type of schema to generate.

**`parameters_callback`** : [`Callable`](https://docs.python.org/3/library/typing.html#typing.Callable)\[\[[`int`](https://docs.python.org/3/library/functions.html#int), [`str`](https://docs.python.org/3/library/stdtypes.html#str), [`Any`](https://docs.python.org/3/library/typing.html#typing.Any)\], [`Literal`](https://docs.python.org/3/library/typing.html#typing.Literal)\['skip'\] | [`None`](https://docs.python.org/3/library/constants.html#None)\] | [`None`](https://docs.python.org/3/library/constants.html#None) _Default:_ `None`

A callable that will be invoked for each parameter. The callback should take three required arguments: the index, the name and the type annotation (or [`Parameter.empty`](https://docs.python.org/3/library/inspect.html#inspect.Parameter.empty) if not annotated) of the parameter. The callback can optionally return `'skip'`, so that the parameter gets excluded from the resulting schema.

**`config`** : [`ConfigDict`](/docs/validation/latest/api/pydantic/config/#pydantic.config.ConfigDict) | [`None`](https://docs.python.org/3/library/constants.html#None) _Default:_ `None`

The configuration to use.