**FastAPI** will recognize each of them and take the data from the correct place.

=== "Python 3.10+"

    ```Python hl_lines="16"
    {!> ../../../docs_src/body/tutorial004_py310.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="18"
    {!> ../../../docs_src/body/tutorial004.py!}
    ```

The function parameters will be recognized as follows:

    ) -> CoreSchema:
        return with_info_plain_validator_function(cls._validate)


class DefaultPlaceholder:
    """
    You shouldn't use this class directly.

    It's used internally to recognize when a default value has been overwritten, even
    if the overridden default value was truthy.
    """

    def __init__(self, value: Any):
        self.value = value

    def __bool__(self) -> bool: