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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 add_field(self, fieldname, fieldspec=whoosh_module_fields.TEXT):
 """Add a field in the index of the model. Args: fieldname (Text):
 This parameters register a new field in specified model. fieldspec (Name, optional):
 This option adds various options as were described before. Returns: TYPE: The new schema after deleted is returned. """

    self._whoosh.add_field(fieldname, fieldspec)
    return self._whoosh.schema