code: def which(self, fname):
          
          for pe in os.environ['PATH'].split(os.pathsep):
              checkname = os.path.join(pe, fname)
              if os.access(checkname, os.X_OK) and not os.path.isdir(checkname):
                  return checkname
          return None
docs: Returns the fully qualified path by searching Path of the given
          name