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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 file(self, md5=None, sha1=None, sha256=None, **kwargs):
 """Add File data to Batch object. .. note:: A least one file hash value must be specified. Args: md5 (str, optional):
 The md5 value for this Indicator. sha1 (str, optional):
 The sha1 value for this Indicator. sha256 (str, optional):
 The sha256 value for this Indicator. confidence (str, kwargs):
 The threat confidence for this Indicator. date_added (str, kwargs):
 The date timestamp the Indicator was created. last_modified (str, kwargs):
 The date timestamp the Indicator was last modified. rating (str, kwargs):
 The threat rating for this Indicator. size (str, kwargs):
 The file size for this Indicator. xid (str, kwargs):
 The external id for this Indicator. Returns: obj: An instance of File. """

        indicator_obj = File(md5, sha1, sha256, **kwargs)
        return self._indicator(indicator_obj)