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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def todict(self, complex_tuple=False):
 """Return a dict equivalent to the namelist. Since Fortran variables and names cannot start with the ``_`` character, any keys starting with this token denote metadata, such as starting index. The ``complex_tuple`` flag is used to convert complex data into an equivalent 2-tuple, with metadata stored to flag the variable as complex. This is primarily used to facilitate the storage of the namelist into an equivalent format which does not support complex numbers, such as JSON or YAML. """

        # TODO: Preserve ordering
        nmldict = OrderedDict(self)

        # Search for namelists within the namelist
        # TODO: Move repeated stuff to new functions
        for key, value in self.items():
            if isinstance(value, Namelist):
                nmldict[key] = value.todict(complex_tuple)

            elif isinstance(value, complex) and complex_tuple:
                nmldict[key] = [value.real, value.imag]
                try:
                    nmldict['_complex'].append(key)
                except KeyError:
                    nmldict['_complex'] = [key]

            elif isinstance(value, list):
                complex_list = False
                for idx, entry in enumerate(value):
                    if isinstance(entry, Namelist):
                        nmldict[key][idx] = entry.todict(complex_tuple)

                    elif isinstance(entry, complex) and complex_tuple:
                        nmldict[key][idx] = [entry.real, entry.imag]
                        complex_list = True

                if complex_list:
                    try:
                        nmldict['_complex'].append(key)
                    except KeyError:
                        nmldict['_complex'] = [key]

        # Append the start index if present
        if self.start_index:
            nmldict['_start_index'] = self.start_index

        return nmldict