docs: def get_vdW_settings(self):
          '''Determine the vdW type if using vdW xc functional or correction
          scheme from the input otherwise'''
          xc = self.get_xc_functional().scalars[0].value
          if 'vdw' in xc.lower(): # vdW xc functional
              return Value(scalars=[Scalar(value=xc)])
          else:
              # look for vdw_corr in input
              vdW_dict = {'xdm':'Becke-Johnson XDM', 'ts':
                          'Tkatchenko-Scheffler', 'ts-vdw':
                          'Tkatchenko-Scheffler',
                          'tkatchenko-scheffler':
                          'Tkatchenko-Scheffler', 'grimme-d2': 'Grimme D2', 'dft-d': 'Grimme D2'}
              if self._get_line('vdw_corr', self.inputf, return_string=False, case_sens=False):
                  line = self._get_line('vdw_corr', self.inputf, return_string=True, case_sens=False)
                  vdwkey = str(line.split('=')[-1].replace("'", "").replace(',', '').lower().rstrip())
                  return Value(scalars=[Scalar(value=vdW_dict[vdwkey])])
              return None