docstr: Concats all the df values into one.
  
  Returns:
      ret (pd.DataFrame): Concatenated string.
docstr_tok: ["Concats","all","the","df","values","into","one",".","Returns",":","ret","(","pd.DataFrame",")",":","Concatenated","string","."]
code: def forward(self, df: pd.DataFrame) -> pd.DataFrame:
      """
      Concats all the df values into one.
  
      Returns:
          ret (pd.DataFrame): Concatenated string.
      """
  
      ret = pd.DataFrame()
      ret["output"] = pd.Series(df.fillna("").values.tolist()).str.join(
          ""
      )
      return ret
  
imports: import pandas
  from evadb.functions.abstract.abstract_function import AbstractFunction
label_desc: Use image node_id 3 for calling the Concat obj's underlying member method code with example usage: obj.forward(df) and returns: ret