Factor common code into internal functions.

Clean-up names of static functions.
Use Py_RETURN_NONE macro.
Expose private functions needed to support merge().
Move C imports to the bottom of the Python file.

Lib/heapq.py

@@ -311,16 +311,6 @@ def _siftup_max(heap, pos):
     heap[pos] = newitem
     _siftdown_max(heap, startpos, pos)
 
-# If available, use C implementation
-try:
-    from _heapq import *
-except ImportError:
-    pass
-try:
-    from _heapq import _heapreplace_max
-except ImportError:
-    pass
-
 def merge(*iterables, key=None, reverse=False):
     '''Merge multiple sorted inputs into a single sorted output.
 
@@ -592,6 +582,24 @@ def nlargest(n, iterable, key=None):
     result.sort(reverse=True)
     return [r[2] for r in result]
 
+# If available, use C implementation
+try:
+    from _heapq import *
+except ImportError:
+    pass
+try:
+    from _heapq import _heapreplace_max
+except ImportError:
+    pass
+try:
+    from _heapq import _heapify_max
+except ImportError:
+    pass
+try:
+    from _heapq import _heappop_max
+except ImportError:
+    pass
+
 
 if __name__ == "__main__":