code: def get_reduction_callable(cls, op):
      sep, na_rep = op.sep, op.na_rep
  
      def str_concat(obj):
          return build_str_concat_object(obj, sep=sep, na_rep=na_rep)
  
      return str_concat
  
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 6 for calling the DataFrameStrConcat obj's underlying member method code with example usage: obj.get_reduction_callable(cls, op) and returns: str_concat, build_str_concat_object