def find_revision_id(self, revision=None):
<EOL>self.create()<EOL>revision = self.expand_branch_name(revision)<EOL>output = self.context.capture('<STR_LIT>', '<STR_LIT>', revision)<EOL>return self.ensure_hexadecimal_string(output, '<STR_LIT>')<EOL>
Find the global revision id of the given revision.