<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def verify(path):
 """Verify folder file format The folder file format is only valid when there is only one file format present. """

        valid = True
        fifo = SeriesFolder._search_files(path)
        # dataset size
        if len(fifo) == 0:
            valid = False
        # number of different file formats
        fifmts = [ff[1] for ff in fifo]
        if len(set(fifmts)) != 1:
            valid = False
        return valid