Untitled

{
  "errorMessage": "Cannot set a DataFrame with multiple columns to the single column reference_date",
  "errorType": "ValueError",
  "requestId": "94a7c334-8df4-42cc-9404-04baeedc41dd",
  "stackTrace": [
    "  File \"/var/task/lambda_function.py\", line 509, in lambda_handler\n    res = processor.process(persist_z_spread_table=persist_z_spread_table,\n",
    "  File \"/var/task/lambda_function.py\", line 480, in process\n    raise e\n",
    "  File \"/var/task/lambda_function.py\", line 471, in process\n    input_df = self.get_valid_mid_data(persist_z_spread_table=persist_z_spread_table,\n",
    "  File \"/var/task/lambda_function.py\", line 403, in get_valid_mid_data\n    df_issuer_z_spread_table['reference_date'] = df_issuer_z_spread_table.apply(\n",
    "  File \"/opt/python/pandas/core/frame.py\", line 3968, in __setitem__\n    self._set_item_frame_value(key, value)\n",
    "  File \"/opt/python/pandas/core/frame.py\", line 4123, in _set_item_frame_value\n    raise ValueError(\n"
  ]
}