def sim_to_rgba(similarity, edge_color):
    """Convert similarity to RGBA.

    Parameters
    ----------
    similarity : float
        Similarity between two answers.
    edge_color : tuple
        When the graph is plotted, this is the RGB color of the edge
        i.e (0, 0, 1).

    Returns
    -------
    tuple i.e (0, 0, 1, 0.78)
        RGBA values i.e (R, G, B, A).

    """
    RGBA = (
        *edge_color, similarity
    )
    return RGBA