Removed obsolete function and added coments for existing functions.

python/descriptor_pool.h

@@ -32,15 +32,17 @@
 
 #include "protobuf.h"
 
-// Returns a serialized protocol buffer for the given filename, which much have
-// been previously loaded into this DescriptorPool.
-PyObject* PyUpb_DescriptorPool_GetSerializedPb(PyObject* _self,
-                                               const char* filename);
-
+// Returns a Python wrapper object for the given symtab. The symtab must have
+// been created from a Python DescriptorPool originally.
 PyObject* PyUpb_DescriptorPool_Get(const upb_symtab* symtab);
+
+// Given a Python DescriptorPool, returns the underlying symtab.
 upb_symtab* PyUpb_DescriptorPool_GetSymtab(PyObject* pool);
+
+// Returns the default DescriptorPool (a global singleton).
 PyObject* PyUpb_DescriptorPool_GetDefaultPool(void);
 
+// Module-level init.
 bool PyUpb_InitDescriptorPool(PyObject* m);
 
 #endif  // PYUPB_DESCRIPTOR_POOL_H__