Simplify inflated_from logic

compiler/router/graph.py

@@ -57,8 +57,7 @@ class graph:
                 # Probe is blocked if the shape isn't routable
                 if not self.is_routable(blockage):
                     return True
-                if blockage.inflated_from is not None:
-                    blockage = blockage.inflated_from
+                blockage = blockage.get_inflated_from()
                 if blockage.overlaps(probe_shape):
                     continue
                 return True
@@ -83,8 +82,7 @@ class graph:
                 if not self.is_routable(blockage):
                     blocked = True
                     continue
-                if blockage.inflated_from is not None:
-                    blockage = blockage.inflated_from
+                blockage = blockage.get_inflated_from()
                 if self.inside_shape(node.center, blockage):
                     offset = self.router.offset
                     p = node.center

compiler/router/graph_shape.py

@@ -21,6 +21,17 @@ class graph_shape(pin_layout):
         self.inflated_from = inflated_from
 
 
+    def get_inflated_from(self):
+        """
+        Return `self` if `self.inflated_from` is None. Otherwise, return
+        `self.inflated_from`.
+        """
+
+        if self.inflated_from is None:
+            return self
+        return self.inflated_from
+
+
     def inflated_pin(self, spacing=None, multiple=0.5, extra_spacing=0, keep_link=False):
         """ Override the default inflated_pin behavior. """