def get_isoforms_from_header(samples_header):
    """
    Given header of a raw MISO samples file, return the isoforms
    field.
    """
    # Get first field (removing prefix comment symbol, '#')
    isoforms = samples_header[1:].split("\t")[0]
    # Remove isoforms= key
    isoforms = isoforms.split("isoforms=")[1]
    # Remove brackets, '[', ']'
    isoforms = isoforms[1:-1]
    
    return isoforms