def insertion(x, y):
    """format: c.[112_113insAGA]"""
    mutations = []
    x = x.upper()
    y = y.upper()
    i = 0
    l = 0 # nucleotides count (excluding gaps)
    while i < len(x):
        if x[i] == "-":
            j = i
            has_gap = True
            i += 1
            while has_gap:
                if x[i] != "-":
                    mutations.append("{}_{}ins{}".format(l, l+1, y[j:i]))
                    has_gap = False
                    i += 1
                    l += 1
                else:
                    i += 1
        else:
            i += 1
            l += 1
    return(mutations)