def getMainDFsavedInStep(path_to_results, path_to_directory, file_name, ending):
    """
    A function used to return a dataframe of data stored in a file at a given path. Not specific to a dataframe of wells in h5 file like load_prev_results_at_path.
    
    Parameters
    ----------
    path_to_results: string
        A path to a top-level results folder.

    path_to_directory: string
        A path to a folder within the results folder that has the file in question.

    file_name: string
        A path to a file within the path_to_results and path_to_directory arguments.
    
    ending: string
        String representation of the file type like ".h5" or ".csv". It should include the dot!

    Returns
    -------
    full_path_to_results_file: string
        Returns a string representation of the full path to the file in question.

    """
    dir_path = path_to_results + "/" + path_to_directory
    full_path_to_results_file = dir_path + "/" + file_name + ending
    return full_path_to_results_file