<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def connectivity(self, bus):
 """check connectivity of network using Goderya's algorithm"""

        if not self.n:
            return
        n = self.nb
        fr = self.a1
        to = self.a2
        os = [0] * self.n

        # find islanded buses
        diag = list(
            matrix(
                spmatrix(self.u, to, os, (n, 1), 'd') +
                spmatrix(self.u, fr, os, (n, 1), 'd')))
        nib = bus.n_islanded_buses = diag.count(0)
        bus.islanded_buses = []
        for idx in range(n):
            if diag[idx] == 0:
                bus.islanded_buses.append(idx)

        # find islanded areas
        temp = spmatrix(
            list(self.u) * 4, fr + to + fr + to, to + fr + fr + to, (n, n),
            'd')
        cons = temp[0, :]
        nelm = len(cons.J)
        conn = spmatrix([], [], [], (1, n), 'd')
        bus.island_sets = []
        idx = islands = 0
        enum = 0

        while 1:
            while 1:
                cons = cons * temp
                cons = sparse(cons)  # remove zero values
                new_nelm = len(cons.J)
                if new_nelm == nelm:
                    break
                nelm = new_nelm
            if len(cons.J) == n:  # all buses are interconnected
                return
            bus.island_sets.append(list(cons.J))
            conn += cons
            islands += 1
            nconn = len(conn.J)
            if nconn >= (n - nib):
                bus.island_sets = [i for i in bus.island_sets if i != []]
                break

            for element in conn.J[idx:]:
                if not diag[idx]:
                    enum += 1  # skip islanded buses
                if element <= enum:
                    idx += 1
                    enum += 1
                else:
                    break

            cons = temp[enum, :]