code: def build_str_concat_object(df, sep=None, na_rep=None):
      output_type = (
          OutputType.series if df.ndim == 2 else OutputType.scalar
      )
      op = DataFrameStrConcat(
          sep=sep, na_rep=na_rep, output_types=[output_type]
      )
      return op(df)
  
file_path: mars/mars/dataframe/reduction/str_concat.py
imports: from ...None import opcodes
  from ...core import OutputType
  from ...serialization.serializables import StringField
  from .core import DataFrameReductionOperand, DataFrameReductionMixin
label_desc: Use image node_id 1 for calling a global function with example usage: build_str_concat_object(df, sep, na_rep) and returns: op