How to use the invocations.docs function in invocations

from invoke import Collection
from invocations import docs

ns = Collection(docs)
ns.configure({
    'sphinx': {
        'source': '.',
        'target': '_build',
        'target_file': 'index.html',
    },

from invocations import docs, checks, travis
from invocations.pytest import test, integration
from invocations.packaging import release

from invoke import Collection


ns = Collection(test, integration, release, docs, travis, checks.blacken)
ns.configure(
    {
        "travis": {"black": {"version": "18.6b4"}},
        "packaging": {
            "sign": True,
            "wheel": True,
            "changelog_file": join(
                docs.ns.configuration()["sphinx"]["source"], "changelog.rst"
            ),