def get_backspace_count(self, buffer):
if TriggerMode.ABBREVIATION in self.modes and self.backspace:<EOL><INDENT>if self._should_trigger_abbreviation(buffer):<EOL><INDENT>abbr = self._get_trigger_abbreviation(buffer)<EOL>stringBefore, typedAbbr, stringAfter = self._partition_input(buffer, abbr)<EOL>return len(abbr) + len(stringAfter)<EOL><DEDENT><DEDENT>if self.parent is not None:<EOL><INDENT>return self.parent.get_backspace_count(buffer)<EOL><DEDENT>return <NUM_LIT:0><EOL>
Given the input buffer, calculate how many backspaces are needed to erase the text
that triggered this folder.