docs: def parse_log(log, url_pattern):
      """Parse ``log`` buffer based on ``url_pattern``.
  
      Given a buffer as ``log``, parse the log buffer into
      a mapping of ident-hashes to a hit count,
      the timestamp of the initial log,
      and the last timestamp in the log.
      """
      hits = {}
      initial_timestamp = None
  
      def clean_timestamp(v):
          return ' '.join(v).strip('[]')
      for line in log:
          data = line.split()
          if not initial_timestamp:
              initial_timestamp = clean_timestamp(data[3:5])
          match = url_pattern.match(data[6])
          if match:
              ident_hash = '@'.join(match.groups())
              if ident_hash:
                  hits[ident_hash] = hits.get(ident_hash, 0) + 1
      else:
          end_timestamp = clean_timestamp(data[3:5])
      return hits, initial_timestamp, end_timestamp