def set_indent(paragraph, left_indent=None, right_indent=None, first_line_indent=None, hanging_indent=None):
    """
    设置缩进，单位为字符
    :param paragraph: 段落
    :param left_indent: 左缩进
    :param right_indent: 右缩进
    :param first_line_indent: 首行缩进， 大于0
    :param hanging_indent: 悬挂缩进,小于0
    """
    assert not all([first_line_indent, hanging_indent]), '首行缩进与悬挂缩进不可同时设置'
    pPr = paragraph._element.get_or_add_pPr()
    ind = OxmlElement('w:ind')
    if left_indent:
        ind.set(qn('w:leftChars'), str(left_indent * 100))
    if right_indent:
        ind.set(qn('w:rightChars'), str(right_indent * 100))
    if first_line_indent:
        ind.set(qn('w:firstLineChars'), str(first_line_indent * 100))
    if hanging_indent:
        ind.set(qn('w:hangingChars'), str(hanging_indent * 100))
    pPr.append(ind)