def _extract_coeffs(self, imt):
        """
        Extract dictionaries of coefficients specific to required
        intensity measure type.
        """
        C_HR = self.COEFFS_HARD_ROCK[imt]
        C_BC = self.COEFFS_BC[imt]
        C_SR = self.COEFFS_SOIL_RESPONSE[imt]
        SC = self.COEFFS_STRESS[imt]

        return C_HR, C_BC, C_SR, SC
Extract dictionaries of coefficients specific to required
        intensity measure type.