def get_consonants(text_string):
    """Given a string, return a list of unique consonants within that string"""
    found_consonants = []
    if text_string:
        consonants = "bcdfghjklmnpqrstvwxyz"
        for char in text_string.lower():
            if char in consonants:
                found_consonants.append(char)
    #remove duplicates
    return list(set(found_consonants))