Takes a list of subtitle (srt) filenames, search term and search type
    and, returns a list of timestamps for composing a supercut.

def compose_from_srts(srts, search, searchtype):
    """Takes a list of subtitle (srt) filenames, search term and search type
    and, returns a list of timestamps for composing a supercut.
    """
    composition = []
    foundSearchTerm = False

    # Iterate over each subtitles file.
    for srt in srts:

        print(srt)
        lines = clean_srt(srt)

        videofile = ""
        foundVideoFile = False

        print("[+] Searching for video file corresponding to '" + srt + "'.")
        for ext in usable_extensions:
            tempVideoFile = srt.replace('.srt', '.' + ext)
            if os.path.isfile(tempVideoFile):
                videofile = tempVideoFile
                foundVideoFile = True
                print("[+] Found '" + tempVideoFile + "'.")

        # If a correspndong video file was found for this subtitles file...
        if foundVideoFile:

            # Check that the subtitles file contains subtitles.
            if lines:

                # Iterate over each line in the current subtitles file.
                for timespan in lines.keys():
                    line = lines[timespan].strip()

                    # If this line contains the search term
                    if search_line(line, search, searchtype):

                        foundSearchTerm = True

                        # Extract the timespan for this subtitle.
                        start, end = convert_timespan(timespan)

                        # Record this occurance of the search term.
                        composition.append({'file': videofile, 'time': timespan, 'start': start, 'end': end, 'line': line})

                # If the search was unsuccessful.
                if foundSearchTerm is False:
                    print("[!] Search term '" + search + "'" + " was not found is subtitle file '" + srt + "'.")

            # If no subtitles were found in the current file.
            else:
                print("[!] Subtitle file '" + srt + "' is empty.")

        # If no video file was found...
        else:
            print("[!] No video file was found which corresponds to subtitle file '" + srt + "'.")
            print("[!] The following video formats are currently supported:")
            extList = ""
            for ext in usable_extensions:
                extList += ext + ", "
            print(extList)

    return composition