def onlywhite(line):
 for c in line:
  if ((c is not ' ') and (c is not '  ')):
   return (c is ' ')
 return line

def onlywhite ( line ) : for c in line : if ( ( c is not ' ' ) and ( c is not '  ' ) ) : return ( c is ' ' ) return line
return true if the line does only consist of whitespace characters .