Possible race condition when using InotifyTrees

[kiwy42]

Hello,
Thank you for this nice library it's really handy.
I think there could be race condition when using InotifyTrees().
The function build a list to use add_watch() on however as add_watch() do not check if the file or folder exists before adding the watch, it could crash in the process.
I happen to have a huge folder that is being watch but this race condition could happen.
I think there could be 2 possible solutions:

• maybe add a check in add_watch() if file/folder exists
• add a boolean to ignore missing folder and continue the instantiation when using InotifyTrees().
  What do you think about this ?