Revert "Fixed Graph: prepare function should work without semiring"
Revert "Fixed Graph: prepare function should work without semiring"

This reverts commit 570a90ab4efc445b99e179eb5424f484be1f011c.

char-lie/mfm,char-lie/patterns_recognition,char-lie/mfm,char-lie/mfm,char-lie/patterns_recognition