private PsiFile addCandidatesFromExistingImports() {
    PsiFile existingImportFile = null; // if there's a matching existing import, this is the file it imports
    PsiFile file = myNode.getContainingFile();
    if (file instanceof PyFile pyFile) {
      for (PyImportElement importElement : pyFile.getImportTargets()) {
        existingImportFile = addImportViaElement(existingImportFile, importElement, importElement.resolve());
      }
      existingImportFile = addCandidatesViaFromImports(existingImportFile, pyFile);
    }
    return existingImportFile;
  }
private PsiFile addCandidatesFromExistingImports()