code: def set_pkg_license_declared(self, doc, lic):
          
          self.assert_package_exists()
          if not self.package_license_declared_set:
              self.package_license_declared_set = True
              if validations.validate_lics_conc(lic):
                  doc.package.license_declared = lic
                  return True
              else:
                  raise SPDXValueError('Package::LicenseDeclared')
          else:
              raise CardinalityError('Package::LicenseDeclared')
docs: Sets the package's declared license.
          Raises SPDXValueError if data malformed.
          Raises OrderError if no package previously defined.
          Raises CardinalityError if already set.