property new checker

lib/python/pyflyby/_autoimp.py

@@ -346,7 +346,7 @@ class _UseChecker:
     An object that can check whether it was used.
     """
 
-    used: bool = False
+    _used: bool = False
     name: str
     source: str
     lineno: int
@@ -355,9 +355,19 @@ def __init__(self, name: str, source: str, lineno: int):
         self.name = name
         self.source = source # generally an Import
         self.lineno = lineno
+        logger.debug("Create _UseChecker : %r", self)
+
+    @property
+    def used(self) -> bool:
+        return self._used
+
+    @used.setter
+    def used(self, value: bool):
+        self._used = value
+        logger.debug("set used for %r to %r", self, value)
 
     def __repr__(self):
-        return f"<{type(self).__name__}: name:{self.name} source:{self.source!r} lineno:{self.lineno} used:{self.used}>"
+        return f"<{type(self).__name__}: name:{self.name!r} source:{self.source!r} lineno:{self.lineno} used:{self.used}>"
 
 
 class _MissingImportFinder: