docs: def execute_builder(self, entry_point, toolchain, spec):
          """
          Accepts the arguments provided by the builder and executes them.
          """
  
          toolchain(spec)
          if not exists(spec['export_target']):
              logger.error(
                  "the entry point '%s' from package '%s' failed to "
                  "generate an artifact at '%s'",
                  entry_point, entry_point.dist, spec['export_target']
              )
              return {}
          return self.generate_metadata_entry(entry_point, toolchain, spec)