Add basic type annotations

[hflamme]

Problem

After updating the version, the interface of some function has changed. My static type checker did not pick it up resulting in unexpected failures.

Solution suggestion

Adding some basic type annotations would have caught this issue upfront.

Example:

from io import BytesIO
from typing import Literal

def get_xml_from_pdf(
    pdf_file: str | bytes | BytesIO, 
    check_xsd: bool = True, 
    check_schematron: bool = True, 
    filenames: list[str] = []
) -> tuple[str | Literal[False], bytes | Literal[False]]:
    ...

or compatible with python 3.7+

from io import BytesIO
from typing import List, Tuple, Union
from typing_extensions import Literal  # for Python 3.7

def get_xml_from_pdf(
    pdf_file: Union[str, bytes, BytesIO],
    check_xsd: bool = True,
    check_schematron: bool = True,
    filenames: List[str] = None,
) -> Tuple[Union[str, Literal[False]], Union[bytes, Literal[False]]]:
    ...

[alexis-via]

Which interface has changed exactly ? Are you referring to release 4.0 that added an named argument check_shematron=True on generate_from_binary(), generate_from_file() and get_xml_from_pdf() ? This was documented in the changelog of the Readme. Or are you referring to another change ?