Fix BaseSubprocessTransport.close()

Ignore pipes for which the protocol is not set yet (still equal to None).

1 files changed, 2 insertions, 0 deletions

diff --git a/asyncio/base_subprocess.py b/asyncio/base_subprocess.py
index d607e8d..f5e7dfe 100644
--- a/asyncio/base_subprocess.py
+++ b/asyncio/base_subprocess.py
@@ -71,6 +71,8 @@ class BaseSubprocessTransport(transports.SubprocessTransport):
 
     def close(self):
         for proto in self._pipes.values():
+            if proto is None:
+                continue
             proto.pipe.close()
         if self._returncode is None:
             self.terminate()