import os 
def search_file(file_name, search_path, pathsep = os.pathsep): 
 for path in search_path.split(pathsep): 
 candidate = os.path.join(path, file_name) 
 if os.path.isfile(candidate): 
 return os.path.abspath(candidate) 
 return None 
search_path = 'd:\pm\pm' 
find_file = search_file('babyos.img', search_path) 
if find_file: 
 print("File 'babyos.img' found at %s" % find_file) 
else: 
 print("File 'babyos.img' not found")