'Same as vim.current.window.buffer.append(), but with tracking changes.'

def append(self, line, line_number=(-1)):

    if (line_number < 0):
        line_number = len(self)
    if (not isinstance(line, list)):
        line = [line]
    self[line_number:line_number] = [as_vimencoding(l) for l in line]
