code: def minWindow(self, s: str, t: str) -> str:
      need = collections.Counter(
          t
      )  # hash table to store char frequency
      missing = len(t)  # total number of chars we care
      start, end = 0, 0
      i = 0
      for j, char in enumerate(s, 1):  # index j from 1
          if need[char] > 0:  # or simply "missing -= need[c] > 0"
              missing -= 1
          need[char] -= 1
          if not missing:  # match all chars
              while (
                  i < j and need[s[i]] < 0
              ):  # remove chars to find the real start
                  need[s[i]] += 1
                  i += 1
              need[
                  s[i]
              ] += 1  # make sure the first appearing char satisfies need[char]>0
              missing += (
                  1  # we missed this first char, so add missing by 1
              )
              if not end or j - i < end - start:  # update window
                  start, end = i, j
              i += 1  # update i to start+1 for next window
      return s[start:end]
  
label_desc: Use image node_id 1 for calling the Solution obj's underlying member method code with example usage: obj.minWindow(s, t) and returns: s