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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 get_point_from_bins_and_idx(self, chi1_bin, chi2_bin, idx):
 """Find masses and spins given bin numbers and index. Given the chi1 bin, chi2 bin and an index, return the masses and spins of the point at that index. Will fail if no point exists there. Parameters chi1_bin : int The bin number for chi1. chi2_bin : int The bin number for chi2. idx : int The index within the chi1, chi2 bin. Returns -------- mass1 : float Mass of heavier body. mass2 : float Mass of lighter body. spin1z : float Spin of heavier body. spin2z : float Spin of lighter body. """

        mass1 = self.massbank[chi1_bin][chi2_bin]['mass1s'][idx]
        mass2 = self.massbank[chi1_bin][chi2_bin]['mass2s'][idx]
        spin1z = self.massbank[chi1_bin][chi2_bin]['spin1s'][idx]
        spin2z = self.massbank[chi1_bin][chi2_bin]['spin2s'][idx]
        return mass1, mass2, spin1z, spin2z