def grid(self, *args):
grids =  map(str,map(float,args))<EOL>self['<STR_LIT>'] = '<STR_LIT:U+002C>'.join(grids).replace('<STR_LIT:None>','<STR_LIT>')<EOL>return self<EOL>
Apply a grid to your chart
args are of the form::
    <x axis step size>,
    <y axis step size>,
    <length of line segment>,
    <length of blank segment>
    <x offset>,
    <y offset>
APIPARAM: chg