How to use the autopep8.ReformattedLines._Indent function in autopep8

def add_indent(self, indent_amt):
        self._lines.append(self._Indent(indent_amt))

def _add_item(self, item, indent_amt):
        """Add an item to the line.

        Reflow the line to get the best formatting after the item is
        inserted. The bracket depth indicates if the item is being
        inserted inside of a container or not.

        """
        if self._prev_item and self._prev_item.is_string and item.is_string:
            # Place consecutive string literals on separate lines.
            self._lines.append(self._LineBreak())
            self._lines.append(self._Indent(indent_amt))

        item_text = unicode(item)
        if self._lines and self._bracket_depth:
            # Adding the item into a container.
            self._prevent_default_initializer_splitting(item, indent_amt)

            if item_text in '.,)]}':
                self._split_after_delimiter(item, indent_amt)

        elif self._lines and not self.line_empty():
            # Adding the item outside of a container.
            if self.fits_on_current_line(len(item_text)):
                self._enforce_space(item)

            else:
                # Line break for the new item.

container.size + self._bracket_depth + 2)
        ):

            if unicode(container)[0] == '(' and self._prev_item.is_name:
                # Don't split before the opening bracket of a call.
                break_after_open_bracket = True
                actual_indent = indent_amt + 4
            elif (
                break_after_open_bracket or
                unicode(self._prev_item) not in '([{'
            ):
                # If the container doesn't fit on the current line and the
                # current line isn't empty, place the container on the next
                # line.
                self._lines.append(self._LineBreak())
                self._lines.append(self._Indent(indent_amt))
                break_after_open_bracket = False
        else:
            actual_indent = self.current_size() + 1
            break_after_open_bracket = False

        if isinstance(container, (ListComprehension, IfExpression)):
            actual_indent = indent_amt

        # Increase the continued indentation only if recursing on a
        # container.
        container.reflow(self, ' ' * actual_indent,
                         break_after_open_bracket=break_after_open_bracket)

def add_line_break_at(self, index, indent_amt):
        self._lines.insert(index, self._LineBreak())
        self._lines.insert(index + 1, self._Indent(indent_amt))