target: Replace Target.__copy__ by __getstate__

__getstate__ is also used by the copy module, but allows pickling the
class as well. This is useful when using the multiprocessing API, which
requires pickling the Target object to send it to the new process.

devlib/target.py

@@ -336,13 +336,14 @@ class Target(object):
         if connect:
             self.connect()
 
-    def __copy__(self):
-        new = self.__class__.__new__(self.__class__)
-        new.__dict__ = self.__dict__.copy()
-        # Avoid sharing the connection instance with the original target, so
-        # that each target can live its own independent life
-        del new.__dict__['_conn']
-        return new
+    def __getstate__(self):
+        return {
+            k: v
+            for k, v in self.__dict__.items()
+            # Avoid sharing the connection instance with the original target,
+            # so that each target can live its own independent life
+            if k != '_conn'
+        }
 
     # connection and initialization