def read_fasta(fname):
    """Read in a Fasta file and returns a list of sequences."""
    temp = []
    seqs = []

    with open(fname, 'r') as f:
        for line in f.readlines():
            if line.startswith('>'):
                temp.append(line[1:].strip())
                seqs.append('')
            else:
                seqs[-1] += line.strip()
    # error checking
    for i in seqs:
        if not i.isalpha():
            raise Exception('Input Error')
    return seqs