code: def _run(self, x, delimiter=None, maxsplit=None):
      if delimiter == "":
          delimiter = None
  
      if x.dtype.kind not in _acceptable_str_dtypes:
          raise TypeError(
              f"Inputs must be string tensors, received dtype {x.dtype}"
          )
      return split_with_padding(x, delimiter, maxsplit)
  
file_path: onnx/onnx/reference/ops/op_string_split.py
imports: from typing import Union
  import numpy
  from onnx.reference.op_run import OpRun
label_desc: Use image node_id 1 for calling the StringSplit obj's underlying member method code with example usage: obj._run(x, delimiter, maxsplit) and returns: split_with_padding