docs: def set_initial_wcxf(self, wc, scale_high=None, get_smpar=False):
          """Load the initial values for Wilson coefficients from a
          wcxf.WC instance.
  
          Parameters:
  
          - `scale_high`: since Wilson coefficients are dimensionless in
            smeftrunner but not in WCxf, the high scale in GeV has to be provided.
            If this parameter is None (default), either a previously defined
            value will be used, or the scale attribute of the WC instance will
            be used.
          - `get_smpar`: boolean, optional, defaults to True. If True, an attempt
            is made to determine the SM parameters from the requirement of
            reproducing the correct SM masses and mixings at the electroweak
            scale. As approximations are involved, the result might or might not
            be reliable, depending on the size of the Wilson coefficients
            affecting the SM masses and mixings. If False, Standard Model
            parameters have to be provided separately and are assumed to be in
            the weak basis used for the Warsaw basis as defined in WCxf,
            i.e. in the basis where the down-type and charged lepton mass
            matrices are diagonal.
          """
          import wcxf
          if wc.eft != 'SMEFT':
              raise ValueError("Wilson coefficients use wrong EFT.")
          if wc.basis != 'Warsaw':
              raise ValueError("Wilson coefficients use wrong basis.")
          if scale_high is not None:
              self.scale_high = scale_high
          elif self.scale_high is None:
              self.scale_high = wc.scale
          C = wcxf.translators.smeft.wcxf2arrays(wc.dict)
          keys_dim5 = ['llphiphi']
          keys_dim6 = list(set(definitions.WC_keys_0f + definitions.WC_keys_2f + definitions.WC_keys_4f) - set(keys_dim5))
          self.scale_in = wc.scale
          for k in keys_dim5:
              if k in C:
                  C[k] = C[k]*self.scale_high
          for k in keys_dim6:
              if k in C:
                  C[k] = C[k]*self.scale_high**2
          C = definitions.symmetrize(C)
          # fill in zeros for missing WCs
          for k, s in definitions.C_keys_shape.items():
              if k not in C and k not in definitions.SM_keys:
                  if s == 1:
                      C[k] = 0
                  else:
                      C[k] = np.zeros(s)
          if self.C_in is None:
              self.C_in = C
          else:
              self.C_in.update(C)
          if get_smpar:
              self.C_in.update(self._get_sm_scale_in())