Fix static typing errors (#187)

Co-authored-by: João Moura <joaomdmoura@gmail.com>

.github/workflows/black.yml

@@ -1,10 +1,10 @@
 name: Lint
 
-on: [push, pull_request]
+on: [pull_request]
 
 jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
-      - uses: psf/black@stable
+      - uses: psf/black@stable

.github/workflows/tests.yml

@@ -1,6 +1,6 @@
 name: Run Tests
 
-on: [push, pull_request]
+on: [pull_request]
 
 permissions:
   contents: write

.github/workflows/type-checker.yml

@@ -0,0 +1,30 @@
+
+name: Run Type Checks
+
+on: [pull_request]
+
+permissions:
+  contents: write
+
+jobs:
+  type-checker:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Setup Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: '3.10'
+
+      - name: Install Requirements
+        run: |
+          sudo apt-get update &&
+          pip install poetry &&
+          poetry lock &&
+          poetry install
+
+      - name: Run type checks
+        run: poetry run pyright