funcsigs

What it is and what it does

funcsigs is a backport of Python 3.3's inspect.signature API to older Python versions. It allows you to introspect function signatures—extracting parameter names, defaults, annotations, and binding arguments to parameters—on Python 2.6, 2.7, and early Python 3 versions that lack native support. The package exports a signature() function that returns a Signature object representing a callable's parameters and return annotation, along with Parameter objects describing each argument and methods like bind() and bind_partial() for argument validation.

This package was most useful during the transition from Python 2 to Python 3, when codebases needed to support both. Modern Python includes inspect.signature natively, making funcsigs obsolete for new projects. The package is abandoned and has not been maintained since its latest release, with no known security vulnerabilities but also no ongoing support.

Use it for:

• Introspect function parameters in Python 2.7 code that needs to validate or document callable signatures.
• Backport signature-based argument validation to legacy Python 3.3–3.5 applications before native support.
• Support older testing or documentation tools that relied on PEP 362 introspection across Python 2 and 3.
• Maintain compatibility in libraries that must support both Python 2 and early Python 3 simultaneously.

Worth the install?

AI-flagged interpretation of the facts on this page — verify before relying

Provides Python function signature introspection (PEP 362) for Python 2.6, 2.7, and 3.3+, backporting the inspect.signature API from Python 3.3 to older versions.

No. This package is abandoned (last release 2016-04-25) and targets Python versions that are themselves out of support. Modern Python includes inspect.signature natively. Install only if you are maintaining legacy Python 2.6–2.7 or Python 3.3–3.5 code that has no path to upgrade; for any new project or modern codebase, use the built-in inspect module instead.

Install

funcsigs on PyPI

pip install funcsigs

uv add funcsigs

poetry add funcsigs

Installing funcsigs

Before you install

Installation is straightforward with no runtime dependencies. However, the package is abandoned—last released 2016-04-25 and unmaintained since. It targets Python 2.6, 2.7, and 3.3–3.5, versions that are themselves long out of support.

License in practice

Licensed under Apache Software License (permissive). No licensing restrictions on use or redistribution.

Quickstart

pip install funcsigs

from funcsigs import signature

def example(a, b=None, *args, **kwargs):
    pass

sig = signature(example)
print(sig.parameters)

Designed for Python 2.6, 2.7, and 3.3–3.5; modern Python versions have inspect.signature built-in and should not need this backport.

Verify before relying

• Whether the package works correctly on modern Python versions despite targeting only 2.6–3.5.
• Current state of PyPy compatibility (documentation notes PyPy3 CI was failing at last release).
• Whether any downstream projects still actively depend on this package or if it is purely legacy.

Package facts

Evidence: funcsigs-1.0.2-py2.py3-none-any.whl

Tags

More Python Modules packages