Add missing Python function docstrings (#13105)

* Add missing Python function docstrings

* Auto-format by https://ultralytics.com/actions

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Co-authored-by: UltralyticsAssistant <web@ultralytics.com>
Co-authored-by: Ultralytics Assistant <135830346+UltralyticsAssistant@users.noreply.github.com>

models/yolo.py

@@ -242,13 +242,14 @@ def __init__(self, cfg="yolov5s.yaml", ch=3, nc=None, anchors=None):
         # Build strides, anchors
         m = self.model[-1]  # Detect()
         if isinstance(m, (Detect, Segment)):
-            s = 256  # 2x min stride
-            m.inplace = self.inplace
 
-            def forward(x):
+            def _forward(x):
+                """Passes the input 'x' through the model and returns the processed output."""
                 return self.forward(x)[0] if isinstance(m, Segment) else self.forward(x)
 
-            m.stride = torch.tensor([s / x.shape[-2] for x in forward(torch.zeros(1, ch, s, s))])  # forward
+            s = 256  # 2x min stride
+            m.inplace = self.inplace
+            m.stride = torch.tensor([s / x.shape[-2] for x in _forward(torch.zeros(1, ch, s, s))])  # forward
             check_anchor_order(m)
             m.anchors /= m.stride.view(-1, 1, 1)
             self.stride = m.stride

utils/loggers/__init__.py

@@ -23,6 +23,7 @@
 except ImportError:
 
     def SummaryWriter(*args):
+        """Fall back to SummaryWriter returning None if TensorBoard is not installed."""
         return None  # None = SummaryWriter(str)