Determine how many sequences there are in fasta file/stream.

    :param fileh: the stream to read the fasta data from, or a string giving
                  the filename of the file to load. Note that if a stream is
                  given, it will be consumed by this function
    :return: the number of sequences in this fasta stream/file

def num_sequences(fileh):
  """
    Determine how many sequences there are in fasta file/stream.

    :param fileh: the stream to read the fasta data from, or a string giving
                  the filename of the file to load. Note that if a stream is
                  given, it will be consumed by this function
    :return: the number of sequences in this fasta stream/file
  """
  if type(fileh).__name__ == "str":
    fh = open(fileh)
  else:
    fh = fileh
  count = 0
  for _ in fastaIterator(fh):
    count += 1
  return count