class_docstr: Holds the ops for each dtypes signature like ('ff->f', func1)
  and allows to do look ups for these
code: def _determine_from_signature(self, signature):
      # Lets convert the signature as it can be a tuple of tuples
      # or a string
      if isinstance(signature, tuple):
          # create a string to do a look-up on the ops
          if len(signature) == 1:
              raise TypeError(
                  "The use of a length 1 tuple for the ufunc `signature` is"
                  " not allowed. Use `dtype` or  fill the tuple with"
                  " `None`s."
              )
          nin = self._nin
          nout = self._nout
          if len(signature) != (nin + nout):
              raise TypeError(
                  "A type-tuple must be specified of length 1 or 3 for ufunc"
                  f" {self._name}"
              )
          signature = (
              "".join(numpy.dtype(t).char for t in signature[:nin])
              + "->"
              + "".join(
                  numpy.dtype(t).char
                  for t in signature[nin : nin + nout]
              )
          )
  
      if isinstance(signature, str):
          is_out = len(signature) == 1
          for op in self._ops:
              if is_out:
                  for t in op.out_types:
                      if t.char != signature:
                          break
                  else:
                      return op
              else:
                  if op.sig_str == signature:
                      return op
      raise TypeError(
          "No loop matching the specified signature and"
          f" casting was found for ufunc {self._name}"
      )
  
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 6 for calling the _OpsRegister obj's underlying member method code with example usage: obj._determine_from_signature(signature) and returns: op, op