inherit from io.RawIOBase in SerialBase instead of everywhere else
diff --git a/serial/serialposix.py b/serial/serialposix.py
index cc41a8d..2052f74 100644
--- a/serial/serialposix.py
+++ b/serial/serialposix.py
@@ -14,7 +14,6 @@
import errno
import fcntl
-import io
import os
import select
import struct
@@ -270,7 +269,7 @@
CMSPAR = 0o10000000000 # Use "stick" (mark/space) parity
-class Serial(SerialBase, io.RawIOBase, PlatformSpecific):
+class Serial(SerialBase, PlatformSpecific):
"""\
Serial port class POSIX implementation. Serial port configuration is
done with termios and fcntl. Runs on Linux and many other Un*x like