hide the python code part from shell parsers

This works around a syntax warning of the continuous integration system.
The cause of this warning could have never triggered anyway.
This commit encloses the whole python code safely in a "here" document.

plugins/network/ath9k_

@@ -53,6 +53,10 @@ else
     python3 "$0" "$@"
 fi
 exit $?
+
+# For shell: ignore everything starting from here until the last line of this file.
+# This is necessary for syntax checkers that try to complain about invalid shell syntax below.
+true <<EOF
 """
 
 
@@ -450,3 +454,7 @@ if __name__ == "__main__":
     # output values
     for item in ath9k.get_values(get_scope()):
         print(item)
+
+# final marker for shell / python hybrid script (see "Interpreter Selection")
+EOF = True
+EOF