Add more type hints (#219)

* No need to copy if just checking

* Reduce isinstance checks, rely on mypy instead

* Update core.py

* Update core.py

* Update core.py

* Update core.py

* Update core.py

* Update test_core.py

* Update core.py

* Update core.py

* Update core.py

* Update core.py

* Update core.py

* Update core.py

* Update core.py

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Update core.py

* Update core.py

* Update core.py

* Update core.py

* Update core.py

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* factorize_multiple refactor

* Update core.py

* Update core.py

* enable experimental

* Update pyproject.toml

* Update core.py

* Update pyproject.toml

* Update core.py

* Update core.py

* Update core.py

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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: Illviljan