error when empty line in .ics file

[ni720]

thanks for this handy tool!

when i started the conversion it gave this error:

Traceback (most recent call last):
  File "ics_to_todotxt.py", line 188, in <module>
    sys.exit(main(sys.argv))
  File "ics_to_todotxt.py", line 155, in main
    todos = ICSParser(codecs.open(input_file_name,
  File "ics_to_todotxt.py", line 53, in __init__
    if line[0] == ' ':
IndexError: string index out of range

In my case it was due to an empty line in the description of an event or a line with just spaces in it.

Filtering out all "empty" lines before parsing should fix the problem.