Inherited methods:
from snip%
adjust-cursor
blink-caret
can-do-edit-operation?
copy
do-edit-operation
draw
find-scroll-step
get-admin
get-count
get-extent
get-flags
get-num-scroll-steps
get-scroll-step-offset
get-snipclass
get-style
get-text
get-text!
is-owned?
match?
merge-with
next
on-char
on-event
own-caret
partial-offset
previous
release-from-owner
resize
set-admin
set-count
set-flags
set-snipclass
set-style
set-unmodified
size-cache-invalid
split
write

graph-snip-mixin : (class? . -> . class?)
  argument extends/implements: snip%
  result implements: graph-snip<%>