code: private function findMigrationPath($namespace)
      {
          if (empty($namespace)) {
              return is_array($this->migrationPath) ? reset($this->migrationPath) : $this->migrationPath;
          }
  
          if (!in_array($namespace, $this->migrationNamespaces, true)) {
              throw new Exception("Namespace '{$namespace}' not found in `migrationNamespaces`");
          }
  
          return $this->getNamespacePath($namespace);
      }
docs: Finds the file path for the specified migration namespace.
  @param string|null $namespace migration namespace.
  @return string migration file path.
  @throws Exception on failure.
  @since 2.0.10