PyO3: Add CI (#1135)

* Add PyO3 ci

* Update python.yml

* Format `bert.py`

.github/workflows/python.yml

@@ -0,0 +1,62 @@
+name: PyO3-CI
+
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - main
+    paths:
+      - candle-pyo3/**
+  pull_request:
+    paths:
+      - candle-pyo3/**
+
+jobs:
+  build_and_test:
+    name: Check everything builds & tests
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest] # For now, only test on Linux
+    steps: 
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
+      - name: Install Rust
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+
+      - name: Install Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: 3.11
+          architecture: "x64"
+
+      - name: Cache Cargo Registry
+        uses: actions/cache@v1
+        with:
+          path: ~/.cargo/registry
+          key: ${{ runner.os }}-cargo-registry-${{ hashFiles('**/Cargo.lock') }}
+
+      - name: Install
+        working-directory: ./candle-pyo3
+        run: |
+          python -m venv .env
+          source .env/bin/activate
+          pip install -U pip
+          pip install pytest maturin black
+          python -m maturin develop -r
+
+      - name: Check style
+        working-directory: ./candle-pyo3
+        run: |
+          source .env/bin/activate
+          python stub.py --check
+          black --check .
+
+      - name: Run tests
+        working-directory: ./candle-pyo3
+        run: |
+          source .env/bin/activate
+          python -m pytest -s -v tests

candle-pyo3/py_src/candle/models/bert.py

@@ -59,8 +59,7 @@ class BertSelfAttention(Module):
         attention_scores = attention_scores / float(self.attention_head_size) ** 0.5
         if attention_mask is not None:
             b_size, _, _, last_dim = attention_scores.shape
-            attention_scores = attention_scores.broadcast_add(
-                    attention_mask.reshape((b_size, 1, 1, last_dim)))
+            attention_scores = attention_scores.broadcast_add(attention_mask.reshape((b_size, 1, 1, last_dim)))
         attention_probs = F.softmax(attention_scores, dim=-1)
 
         context_layer = attention_probs.matmul(value)
@@ -198,7 +197,9 @@ class BertModel(Module):
         self.encoder = BertEncoder(config)
         self.pooler = BertPooler(config) if add_pooling_layer else None
 
-    def forward(self, input_ids: Tensor, token_type_ids: Tensor, attention_mask=None) -> Tuple[Tensor, Optional[Tensor]]:
+    def forward(
+        self, input_ids: Tensor, token_type_ids: Tensor, attention_mask=None
+    ) -> Tuple[Tensor, Optional[Tensor]]:
         if attention_mask is not None:
             # Replace 0s with -inf, and 1s with 0s.
             attention_mask = masked_fill(float("-inf"), attention_mask, 1.0)