Comments in lftp script file

[Cyrus Mehta]

I want to put generic documentation comments into an lftp script file when
called from the command line like "lftp -f /myscript.lftp"

What is the comment character to put in front of a text line?  Is it "#" or
"--"?

Also is it possible to make a lftp script executable by doing something
like:
      #!/opt/bin/lftp -f
at the top of a script?

Thanks in advance!  -- Cyrus