def plot_2D_lines(df, columns, limits):
    """Plot multiple columms of a pandas dataframe on a line graph.
    
    Args:
    df      (dataframe): pandas dataframe to plot, must contain x,y and z for now
    columns      (list): list containing xmin,xmax,ymin,ymax,zmin,zmax
    
    Returns:
    bool: list of pandas dataframes containing 3D tracks.
    """
    if type(columns) is list:
        ax = df.plot(y=columns[0], use_index=True)
        for i in range(len(columns) - 1):
            df.plot(y=columns[i + 1], ax=ax, use_index=True)
