code: def search(cls, name, lookup=None):
          
  
          for spath in lookup:
              spath = os.path.abspath(spath) + os.sep
              fname = os.path.abspath(os.path.join(spath, name))
              if not fname.startswith(spath): continue
              if os.path.isfile(fname): return fname
              for ext in cls.extensions:
                  if os.path.isfile('%s.%s' % (fname, ext)):
                      return '%s.%s' % (fname, ext)
docs: Search name in all directories specified in lookup.
          First without, then with common extensions. Return first hit.