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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 is_symbols_pair_complete(editor, symbol):
 """ Returns if the symbols pair is complete on current editor line. :param editor: Document editor. :type editor: QWidget :param symbol: Symbol to check. :type symbol: unicode :return: Is symbols pair complete. :rtype: bool """


    symbols_pairs = get_editor_capability(editor, "symbols_pairs")
    if not symbols_pairs:
        return

    cursor = editor.textCursor()
    cursor.movePosition(QTextCursor.StartOfLine, QTextCursor.MoveAnchor)
    cursor.movePosition(QTextCursor.EndOfLine, QTextCursor.KeepAnchor)
    selected_text = foundations.strings.to_string(cursor.selectedText())
    if symbol == symbols_pairs[symbol]:
        return selected_text.count(symbol) % 2 == 0
    else:
        return selected_text.count(symbol) == selected_text.count(symbols_pairs[symbol])