Store a new variant Mapping for the current Frame in a FrameSet   astAddVariant 
  
" Variant" attribute for more details. It can also be used to
rename the currently selected variant Mapping.  " name" , but no
new variant is added.  " map" is NULL).  The newly added Variant becomes the current variant on exit (this is equivalent to
setting the Variant attribute to the value supplied for " name).
An error is reported if a variant with the supplied name already exists in the current Frame.
An error is reported if the current Frame is a mirror for the variant Mappings in another Frame. This is only the case if the astMirrorVariants function has been called to make the current Frame act as a mirror.