code: def meta(r):
      
  
      r = r.split()
      # :todo: raise FormatError
      assert len(r) == 5
      r = [r[0]] + map(int, r[1:])
      return r
docs: Convert 60 character string `r`, the metadata from an image file.
      Returns a 5-tuple (*chan*,*minx*,*miny*,*limx*,*limy*).  5-tuples may
      settle into lists in transit.
  
      As per http://plan9.bell-labs.com/magic/man2html/6/image the metadata
      comprises 5 words separated by blanks.  As it happens each word starts
      at an index that is a multiple of 12, but this routine does not care
      about that.