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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def sequence_charge(seq, pH=7.4):
 """Calculates the total charge of the input polypeptide sequence. Parameters seq : str Sequence of amino acids. pH : float pH of interest. """

    if 'X' in seq:
        warnings.warn(_nc_warning_str, NoncanonicalWarning)
    adj_protein_charge = sum(
        [partial_charge(aa, pH) * residue_charge[aa] * n
         for aa, n in Counter(seq).items()])
    adj_protein_charge += (
        partial_charge('N-term', pH) * residue_charge['N-term'])
    adj_protein_charge += (
        partial_charge('C-term', pH) * residue_charge['C-term'])
    return adj_protein_charge