Parse the core contribution of NMR chemical shielding.

            Returns:
            G0 contribution matrix as list of list.

def read_cs_core_contribution(self):
        """
            Parse the core contribution of NMR chemical shielding.

            Returns:
            G0 contribution matrix as list of list.
        """
        header_pattern = r'^\s+Core NMR properties\s*$\n' \
                         r'\n' \
                         r'^\s+typ\s+El\s+Core shift \(ppm\)\s*$\n' \
                         r'^\s+-{20,}$\n'
        row_pattern = r'\d+\s+(?P<element>[A-Z][a-z]?\w?)\s+(?P<shift>[-]?\d+\.\d+)'
        footer_pattern = r'\s+-{20,}\s*$'
        self.read_table_pattern(header_pattern, row_pattern, footer_pattern, postprocess=str,
                                last_one_only=True, attribute_name="cs_core_contribution")
        core_contrib = {d['element']: float(d['shift'])
                        for d in self.data["cs_core_contribution"]}
        self.data["cs_core_contribution"] = core_contrib