class_docstr: Holds the ops for each dtypes signature like ('ff->f', func1)
  and allows to do look ups for these
code: def determine_dtype(self, args, dtype, casting, signature):
      ret_dtype = None
      func = self._default_func
      if signature is not None:
          # TODO(ecastill) use an externally provided signature to
          # find the typecasting rules
          op = self._determine_from_signature(signature)
      elif dtype is not None:
          if type(dtype) == tuple:
              # TODO(ecastill) support dtype tuples
              raise RuntimeError(
                  "dtype with tuple is not yet supported"
              )
          op = self._determine_from_dtype(dtype)
      else:
          op = self._determine_from_args(args, casting)
  
      if op is None:
          # Should we allow op to be none?
          if dtype is None:
              dtype = args[0].dtype
              for arg in args:
                  ret_dtype = numpy.promote_types(dtype, arg.dtype)
          else:
              ret_dtype = get_dtype(dtype)
      else:
          # Convert args to the op specified in_types
          n_args = []
  
          def argname():
              return f"ufunc {self._name} input {i}"
  
          for i, (arg, in_type) in enumerate(zip(args, op.in_types)):
              _raise_if_invalid_cast(
                  arg.dtype, in_type, casting, argname
              )
  
              n_args.append(arg.astype(in_type, copy=False))
          args = n_args
          ret_dtype = op.out_types[0]
          func = op.func
  
      return args, ret_dtype, func
  
imports: import re
  import numpy
  import cupy
  import cupy._core._routines_manipulation
  from cupy._core._dtype import get_dtype, _raise_if_invalid_cast
  from cupy._core import internal
label_desc: Use image node_id 7 for calling the _OpsRegister obj's underlying member method code with example usage: obj.determine_dtype(args, dtype, casting, signature) and returns: args,  ret_dtype,  func, str, self, str, i