Fixed #1403 where compileall and py_compile choked on an encoding header in a py file. Both modules need more unit tests.
diff --git a/Lib/io.py b/Lib/io.py
index b305b53..c2f5d3e 100644
--- a/Lib/io.py
+++ b/Lib/io.py
@@ -1063,6 +1063,9 @@
                 else:
                     encoding = locale.getpreferredencoding()
 
+        if not isinstance(encoding, str):
+            raise ValueError("invalid encoding: %r" % encoding)
+
         self.buffer = buffer
         self._encoding = encoding
         self._readuniversal = not newline
diff --git a/Lib/py_compile.py b/Lib/py_compile.py
index f7a2002..912972b 100644
--- a/Lib/py_compile.py
+++ b/Lib/py_compile.py
@@ -88,7 +88,7 @@
                 break
             m = re.match(r".*\bcoding:\s*(\S+)\b", line)
             if m:
-                return str(m.group(1))
+                return m.group(1).decode("ascii")
         return default
     finally:
         f.close()