code: def join(*args, trailing_slash=False):
      
      dirty_path = '/'.join(map(lambda x: x and x or '', args))
      path = re.sub(r'/+', '/', dirty_path)
      if path in {'', '/'}:
          return '/'
      path = path.rstrip('/')
      return path if not trailing_slash else path + '/'
docs: Return a url path joined from the arguments. It correctly handles blank/None
      arguments, and removes back-to-back slashes, eg::
  
          assert join('/', 'foo', None, 'bar', '', 'baz') == '/foo/bar/baz'
          assert join('/', '/foo', '/', '/bar/') == '/foo/bar'
  
      Note that it removes trailing slashes by default, so if you want to keep those,
      then you need to pass the ``trailing_slash`` keyword argument::
  
          assert join('/foo', 'baz', None, trailing_slash=True) == '/foo/baz/'