docs: def spec(self, name):
          """
          Returns either the input corresponding to a fileset or field
          field spec or a spec or parameter that has either
          been passed to the study as an input or can be derived.
  
          Parameters
          ----------
          name : Str | BaseData | Parameter
              A parameter, fileset or field or name of one
          """
          # If the provided "name" is actually a data item or parameter then
          # replace it with its name.
          if isinstance(name, (BaseData, Parameter)):
              name = name.name
          # If name is a parameter than return the parameter spec
          if name in self._param_specs:
              return self._param_specs[name]
          else:
              return self.bound_spec(name)