Convert a normal ipa string into a prostring for Chinese dialects.

def analyze_sequence(ipa):
    """
    Convert a normal ipa string into a prostring for Chinese dialects.
    """
    # we need some very good strategy here, which should be lightwayt and easy
    # to re-implement in other languages (e.g. JS)

    # get sound-class rep of stirng first
    seqs = re.split('([₁₂₃₄₅₆₀¹²³⁴⁵⁶⁰])+', ipa)
    out = ''
    for i in range(len(seqs)):
        seqs = ipa2tokens(tokens2class(ipa, merge_vowels=False, expand_nasals=True),'asjp')
    
        D = {}

        pass