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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def close_buffer(self):
 """ Close current buffer. When there are other windows showing the same buffer, they are closed as well. When no windows are left, the previous buffer or an empty buffer is shown. """

        eb = self.active_editor_buffer

        # Remove this buffer.
        index = self.editor_buffers.index(eb)
        self.editor_buffers.remove(eb)

        # Close the active window.
        self.active_tab.close_active_window()

        # Close all the windows that still have this buffer open.
        for i, t in enumerate(self.tab_pages[:]):
            t.close_editor_buffer(eb)

            # Remove tab when there are no windows left.
            if t.window_count() == 0:
                self.tab_pages.remove(t)

                if i >= self.active_tab_index:
                    self.active_tab_index = max(0, self.active_tab_index - 1)

        # When there are no windows/tabs left, create a new tab.
        if len(self.tab_pages) == 0:
            self.active_tab_index = None

            if len(self.editor_buffers) > 0:
                # Open the previous buffer.
                new_index = (len(self.editor_buffers) + index - 1) % len(self.editor_buffers)
                eb = self.editor_buffers[new_index]

                # Create a window for this buffer.
                self.tab_pages.append(TabPage(Window(eb)))
                self.active_tab_index = 0
            else:
                # Create a new buffer. (This will also create the window
                # automatically.)
                eb = self._get_or_create_editor_buffer()