code: def __init__(self, sep=None, na_rep=None, **kw):
      super().__init__(_sep=sep, _na_rep=na_rep, **kw)
  
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 to create a new DataFrameStrConcat object from inherited base classes: DataFrameReductionOperand, DataFrameReductionMixin with example: obj = DataFrameStrConcat(sep, na_rep)