code: def getfirstmatchingheader(self, name):
          
          name = name.lower() + ':'
          n = len(name)
          lst = []
          hit = 0
          for line in self.headers:
              if hit:
                  if not line[:1].isspace():
                      break
              elif line[:n].lower() == name:
                  hit = 1
              if hit:
                  lst.append(line)
          return lst
docs: Get the first header line matching name.
  
          This is similar to getallmatchingheaders, but it returns only the
          first matching header (and its continuation lines).