'Instantiate new object.
snippets_stack is a slice of currently active snippets.'

def __init__(self, snippets_stack, vstate):

    self._snippets_stack = snippets_stack
    self._buffer = vim.current.buffer
    self._change_tick = int(vim.eval('b:changedtick'))
    self._forward_edits = True
    self._vstate = vstate
