diff --git a/.github/header-checker-lint.yml b/.github/header-checker-lint.yml
new file mode 100644
index 0000000..fc281c0
--- /dev/null
+++ b/.github/header-checker-lint.yml
@@ -0,0 +1,15 @@
+{"allowedCopyrightHolders": ["Google LLC"],
+ "allowedLicenses": ["Apache-2.0", "MIT", "BSD-3"],
+ "ignoreFiles": ["**/requirements.txt", "**/requirements-test.txt"],
+ "sourceFileExtensions": [
+ 	"ts", 
+ 	"js", 
+ 	"java", 
+ 	"sh", 
+ 	"Dockerfile", 
+ 	"yaml", 
+ 	"py",
+ 	"html",
+ 	"txt"
+ ]
+}
\ No newline at end of file
diff --git a/.kokoro/build.sh b/.kokoro/build.sh
index d635855..520b1ff 100755
--- a/.kokoro/build.sh
+++ b/.kokoro/build.sh
@@ -15,7 +15,11 @@
 
 set -eo pipefail
 
-cd github/python-billing
+if [[ -z "${PROJECT_ROOT:-}" ]]; then
+    PROJECT_ROOT="github/python-billing"
+fi
+
+cd "${PROJECT_ROOT}"
 
 # Disable buffering, so that the logs stream through.
 export PYTHONUNBUFFERED=1
@@ -30,16 +34,16 @@ export GOOGLE_APPLICATION_CREDENTIALS=${KOKORO_GFILE_DIR}/service-account.json
 export PROJECT_ID=$(cat "${KOKORO_GFILE_DIR}/project-id.json")
 
 # Remove old nox
-python3.6 -m pip uninstall --yes --quiet nox-automation
+python3 -m pip uninstall --yes --quiet nox-automation
 
 # Install nox
-python3.6 -m pip install --upgrade --quiet nox
-python3.6 -m nox --version
+python3 -m pip install --upgrade --quiet nox
+python3 -m nox --version
 
 # If NOX_SESSION is set, it only runs the specified session,
 # otherwise run all the sessions.
 if [[ -n "${NOX_SESSION:-}" ]]; then
-    python3.6 -m nox -s "${NOX_SESSION:-}"
+    python3 -m nox -s ${NOX_SESSION:-}
 else
-    python3.6 -m nox
+    python3 -m nox
 fi
diff --git a/.kokoro/docs/docs-presubmit.cfg b/.kokoro/docs/docs-presubmit.cfg
index 1118107..def756e 100644
--- a/.kokoro/docs/docs-presubmit.cfg
+++ b/.kokoro/docs/docs-presubmit.cfg
@@ -15,3 +15,14 @@ env_vars: {
     key: "TRAMPOLINE_IMAGE_UPLOAD"
     value: "false"
 }
+
+env_vars: {
+    key: "TRAMPOLINE_BUILD_FILE"
+    value: "github/python-billing/.kokoro/build.sh"
+}
+
+# Only run this nox session.
+env_vars: {
+    key: "NOX_SESSION"
+    value: "docs docfx"
+}
diff --git a/.trampolinerc b/.trampolinerc
index 995ee29..383b6ec 100644
--- a/.trampolinerc
+++ b/.trampolinerc
@@ -24,6 +24,7 @@ required_envvars+=(
 pass_down_envvars+=(
     "STAGING_BUCKET"
     "V2_STAGING_BUCKET"
+    "NOX_SESSION"
 )
 
 # Prevent unintentional override on the default image.
diff --git a/CONTRIBUTING.rst b/CONTRIBUTING.rst
index bef5946..d71b6b7 100644
--- a/CONTRIBUTING.rst
+++ b/CONTRIBUTING.rst
@@ -70,9 +70,14 @@ We use `nox <https://nox.readthedocs.io/en/latest/>`__ to instrument our tests.
 - To test your changes, run unit tests with ``nox``::
 
     $ nox -s unit-2.7
-    $ nox -s unit-3.7
+    $ nox -s unit-3.8
     $ ...
 
+- Args to pytest can be passed through the nox command separated by a `--`. For
+  example, to run a single test::
+
+    $ nox -s unit-3.8 -- -k <name of test>
+
   .. note::
 
     The unit tests and system tests are described in the
@@ -93,8 +98,12 @@ On Debian/Ubuntu::
 ************
 Coding Style
 ************
+- We use the automatic code formatter ``black``. You can run it using
+  the nox session ``blacken``. This will eliminate many lint errors. Run via::
+
+   $ nox -s blacken
 
-- PEP8 compliance, with exceptions defined in the linter configuration.
+- PEP8 compliance is required, with exceptions defined in the linter configuration.
   If you have ``nox`` installed, you can test that you have not introduced
   any non-compliant code via::
 
@@ -133,13 +142,18 @@ Running System Tests
 
 - To run system tests, you can execute::
 
-   $ nox -s system-3.7
+   # Run all system tests
+   $ nox -s system-3.8
    $ nox -s system-2.7
 
+   # Run a single system test
+   $ nox -s system-3.8 -- -k <name of test>
+
+
   .. note::
 
       System tests are only configured to run under Python 2.7 and
-      Python 3.7. For expediency, we do not run them in older versions
+      Python 3.8. For expediency, we do not run them in older versions
       of Python 3.
 
   This alone will not run the tests. You'll need to change some local
diff --git a/MANIFEST.in b/MANIFEST.in
index e9e29d1..e783f4c 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -16,10 +16,10 @@
 
 # Generated by synthtool. DO NOT EDIT!
 include README.rst LICENSE
-recursive-include google *.json *.proto
+recursive-include google *.json *.proto py.typed
 recursive-include tests *
 global-exclude *.py[co]
 global-exclude __pycache__
 
 # Exclude scripts for samples readmegen
-prune scripts/readme-gen
\ No newline at end of file
+prune scripts/readme-gen
diff --git a/google/cloud/billing_v1/__init__.py b/google/cloud/billing_v1/__init__.py
index b010229..1ca4234 100644
--- a/google/cloud/billing_v1/__init__.py
+++ b/google/cloud/billing_v1/__init__.py
@@ -44,7 +44,7 @@
     "AggregationInfo",
     "BillingAccount",
     "Category",
-    "CloudCatalogClient",
+    "CloudBillingClient",
     "CreateBillingAccountRequest",
     "GetBillingAccountRequest",
     "GetProjectBillingInfoRequest",
@@ -63,5 +63,5 @@
     "Sku",
     "UpdateBillingAccountRequest",
     "UpdateProjectBillingInfoRequest",
-    "CloudBillingClient",
+    "CloudCatalogClient",
 )
diff --git a/noxfile.py b/noxfile.py
index a57e24b..70d9c13 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -30,6 +30,17 @@
 SYSTEM_TEST_PYTHON_VERSIONS = ["3.8"]
 UNIT_TEST_PYTHON_VERSIONS = ["3.6", "3.7", "3.8", "3.9"]
 
+# 'docfx' is excluded since it only needs to run in 'docs-presubmit'
+nox.options.sessions = [
+    "unit",
+    "system",
+    "cover",
+    "lint",
+    "lint_setup_py",
+    "blacken",
+    "docs",
+]
+
 
 @nox.session(python=DEFAULT_PYTHON_VERSION)
 def lint(session):
@@ -75,6 +86,7 @@ def default(session):
     session.install(
         "mock", "pytest", "pytest-cov",
     )
+
     session.install("-e", ".")
 
     # Run py.test against the unit tests.
diff --git a/synth.metadata b/synth.metadata
index d405942..70f6093 100644
--- a/synth.metadata
+++ b/synth.metadata
@@ -4,7 +4,7 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/python-billing.git",
-        "sha": "8dbad869521924fc3f7d7dc2d4f5d7e9100874b3"
+        "sha": "65755f9cb54c745a6f9bdd4e23a339e2168eb383"
       }
     },
     {
@@ -19,14 +19,14 @@
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "41a4e56982620d3edcf110d76f4fcdfdec471ac8"
+        "sha": "4679e7e415221f03ff2a71e3ffad75b9ec41d87e"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "41a4e56982620d3edcf110d76f4fcdfdec471ac8"
+        "sha": "4679e7e415221f03ff2a71e3ffad75b9ec41d87e"
       }
     }
   ],
@@ -48,6 +48,7 @@
     ".github/ISSUE_TEMPLATE/feature_request.md",
     ".github/ISSUE_TEMPLATE/support_request.md",
     ".github/PULL_REQUEST_TEMPLATE.md",
+    ".github/header-checker-lint.yml",
     ".github/release-please.yml",
     ".github/snippet-bot.yml",
     ".gitignore",