def create_indexes(x_values: list) -> dict:
    """
    Function that creates indexes for spline coefficients matrix
    :param x_values: our nodes
    :return: dictionary with indexes
    """
    indexes = {}
    length = len(x_values)
    for i in range(length - 1):
        indexes[f'b{i + 1}'] = i
        indexes[f'c{i + 1}'] = i + length - 1
        indexes[f'd{i + 1}'] = i + length * 2 - 2
    indexes['y'] = (length - 1) * 3
    return indexes