def unique_family(data):
    """A list of unique families in the USDA data provided
    
    Iterates through the DictReader for the family names, and returns a list of
    names

    Args:
        A DictReader instance of the usda plant checklist

    Returns:
        A list of strings containing all the unique family names in the list
    """
    unique_family = []
    for line in data:
        if line["Family"] not in unique_family:
            unique_family.append(line["Family"])
    return unique_family