Writes a fasta sequence into a file.

    :param sequence: a string with the sequence to be written
    :param sequence_name: name of the the fasta sequence
    :param output_file: /path/to/file.fa to be written

    :returns: nothing

def writeFasta(sequence, sequence_name, output_file):
    """
    Writes a fasta sequence into a file.

    :param sequence: a string with the sequence to be written
    :param sequence_name: name of the the fasta sequence
    :param output_file: /path/to/file.fa to be written

    :returns: nothing
    """
    i=0
    f=open(output_file,'w')
    f.write(">"+str(sequence_name)+"\n")
    while i <= len(sequence):
        f.write(sequence[i:i+60]+"\n")
        i=i+60
    f.close()