docs: def find_proc_date(header):
      """Search the HISTORY fields of a header looking for the FLIPS
      processing date.
      """
      import string, re
      for h in header.ascardlist():
          if h.key=="HISTORY":
              g=h.value
              if ( string.find(g,'FLIPS 1.0 -:') ):
                  result=re.search('imred: FLIPS 1.0 - \S{3} (.*) - ([\s\d]\d:\d\d:\d\d)\s*$',g)
                  if result:
                      date=result.group(1)
                      time=result.group(2)
                      datetime=date+" "+time
                      return datetime
      return None