docs: def generate_s3_url(files):
      """Takes files from React side, creates
      SolveBio Object containing signed S3 URL."""
      if files:
          vault = g.client.Vault.get_personal_vault()
          files = json.loads(files)
          objects = []
          for i in xrange(len(files)):
              obj = g.client.Object.create(
                  vault_id=vault.id,
                  object_type='file',
                  filename=files[i].get('filename'),
                  mimetype=files[i].get('mimetype'),
                  size=files[i].get('size')
              )
              objects.append({
                  'id': obj.id,
                  'filename': obj.filename,
                  'upload_url': obj.upload_url
              })
          return json.dumps(objects)