code: def emit_single_dispatch(
      ps: PythonSignature,
      f: NativeFunction,
      namedtuple_typenames: Dict[str, str],
      *,
      symint: bool = True,
  ) -> str:
      """
      Emit dispatch code for a single native function.
      """
  
      @with_native_function
      def go(f: NativeFunction) -> str:
          # header comments
          if isinstance(ps, PythonSignatureDeprecated):
              schema_comment = (
                  f"// [deprecated] aten::{ps.deprecated_schema}"
              )
          else:
              schema_comment = f"// aten::{f.func}"
  
          deprecated = "[deprecated] " if ps.deprecated else ""
  
          # dispatch lambda signature
          name = cpp.name(f.func)
          lambda_formals = ", ".join(
              f"{a.type_str} {a.name}"
              for a in dispatch_lambda_args(ps, f, symint=symint)
          )
          lambda_return = dispatch_lambda_return_str(f)
  
          # dispatch lambda body
          dispatch_callee = cpp_dispatch_target(f)
          dispatch_args = ", ".join(
              cpp_dispatch_exprs(f, python_signature=ps)
          )
  
          # from arg parser outputs to dispatch lambda arguments
          parser_outputs = arg_parser_output_exprs(ps, f, symint=symint)
          lambda_arg_exprs = dispatch_lambda_exprs(ps, f, symint=symint)
          inits = "\n".join(lambda_arg_exprs.inits)
          lambda_args = ", ".join(lambda_arg_exprs.exprs)
  
          # scatter fields
          # TODO: Checking `ps.method and ('requires_grad' in parser_outputs)` is a hacky
          #       solution for enabling the 'requires_grad' argument for tensor methods
          #       new_full, new_empty, and new_zeros. A much better but more difficult to
          #       implement solution involves refactoring according to Ed's description here:
          #       https://github.com/pytorch/pytorch/issues/36455#issuecomment-614767589
          need_set_requires_grad = ps.tensor_options_args and (
              not has_tensor_options(f)
              or (ps.method and ("requires_grad" in parser_outputs))
          )
          set_requires_grad = (
              f'.set_requires_grad({parser_outputs["requires_grad"].expr})'
              if need_set_requires_grad
              else ""
          )
  
          if lambda_return == "void":
              return f"""\
  {schema_comment}
  {inits}
  auto dispatch_{name} = []({lambda_formals}) -> {lambda_return} {{
    pybind11::gil_scoped_release no_gil;
    {dispatch_callee}({dispatch_args});
  }};
  dispatch_{name}({lambda_args}){set_requires_grad};
  Py_RETURN_NONE;
  """
          else:
              typename = namedtuple_typenames.get(
                  gen_namedtuple_typename_key(f)
              )
              namedtuple_typeref = (
                  f"{typename}, " if typename is not None else ""
              )
              return f"""\
  {schema_comment}
  {inits}
  auto dispatch_{name} = []({lambda_formals}) -> {lambda_return} {{
    pybind11::gil_scoped_release no_gil;
    return {dispatch_callee}({dispatch_args});
  }};
  return wrap({namedtuple_typeref}dispatch_{name}({lambda_args}){set_requires_grad});
  """
  
      return go(f)
  
imports: import itertools
  import re
  from collections import defaultdict
  from typing import Callable, Dict, Iterable, List, Optional, Sequence, Set, Tuple
  import yaml
  from torchgen.api import cpp
  from torchgen.api.python import arg_parser_output_exprs, cpp_dispatch_exprs, cpp_dispatch_target, dispatch_lambda_args, dispatch_lambda_exprs, dispatch_lambda_return_str, has_tensor_options, namedtuple_fieldnames, PythonSignature, PythonSignatureDeprecated, PythonSignatureGroup, PythonSignatureNativeFunctionPair, signature, signature_from_schema
  from torchgen.code_template import CodeTemplate
  from torchgen.context import with_native_function
  from torchgen.gen import cpp_string, parse_native_yaml, parse_tags_yaml
  from torchgen.model import Argument, BaseOperatorName, FunctionSchema, NativeFunction, Type, Variant
  from torchgen.utils import FileManager, split_name_params
  from torchgen.yaml_utils import YamlLoader
  from .gen_trace_type import should_trace
label_desc: Use image node_id 31 for calling a global function with example usage: emit_single_dispatch(ps, f, namedtuple_typenames) and returns: go, schema_comment, str, inits, str, name, str, lambda_formals, str, lambda_return, str, dispatch_callee, str, dispatch_args, str, name, str, lambda_args, str, set_requires_grad, str, schema_comment, str, inits, str, name, str, lambda_formals, str, lambda_return, str, dispatch_callee, str, dispatch_args, str, namedtuple_typeref, str, name, str, lambda_args, str, set_requires_grad, str