code: def get_pyof_version(module_fullname):
          
          ver_module_re = re.compile(r'(pyof\.)(v0x\d+)(\..*)')
          matched = ver_module_re.match(module_fullname)
          if matched:
              version = matched.group(2)
              return version
          return None
docs: Get the module pyof version based on the module fullname.
  
          Args:
              module_fullname (str): The fullname of the module
                  (e.g.: pyof.v0x01.common.header)
  
          Returns:
              str: openflow version.
                   The openflow version, on the format 'v0x0?' if any. Or None
                   if there isn't a version on the fullname.