res = pdf.FindNext(id, page)
pdf.FindNext() will find the next occurrence of the search string passed
to pdf.FindStart(). If another instance of the search string could be found, pdf.FindNext()
will return True and you can get the information about where the string was found using
pdf.GetFindResult(). Otherwise, False is returned.
The page to use must be specified in the page argument. It must be a number in
the range of 1 to the total number of pages in the document and the page must have
been previously loaded using pdf.LoadPage() with the text argument set
to True. The PDF document specified by id must have been previously opened using
pdf.OpenDocument().
True if the search string could be found, False otherwise