Cython __pyx_r may be used uninitialized in this function

I am trying to utilize cython to provide a wrapper for my C++ utilities. One such function I am trying to make accessible is an accessor that retus an enum based on file type.

Here is how I re-define the function in cython:

cdef exte from "reader.h" namespace "magic_number":
   enum mcr_magic_number_t:                                                                              
      MDI = 0                                                                                            
      EOT                                                                                                
      RV                                                                                                 
      UNKNOWN  

and then in my reader.pxd file I have

cpdef mcr_magic_number_t magic_number(self)

and then in my 'reader.pyx' file I have

cpdef mcr_magic_number_t magic_number(self):            
   """                                           
   :retu: the magic_number enum                       
   :rtype: mcr_magic_number_t                           
   """                                                  
   retu self.thisptr.magic_number() 

Now, when I go to compile this, I get a waing

waing: ‘__pyx_r’ may be used uninitialized in this function

Anyone know how is best to get around this? I tried searching for solutions on google but all I got were pages of other people reporting the same __pyx_r error. Maybe there is a way to set a default value?