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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_has_tag_anchor_keypair(self, anchors, file_key, tag):
 """ Is there an AnchorHub tag, 'tag', registered for file 'file_key' in 'anchors'? :param anchors: Dictionary mapping string file paths to inner dictionaries. These inner dictionaries map string AnchorHub tags to string generated anchors :param file_key: The absolute path to the file that may or may not have the AnchorHub tag in it. Used as a key to anchors :param tag: The string being tested :return: True if tag is a valid AnchorHub tag in the file associated with 'file_key' """

        return file_key in anchors and tag in anchors[file_key]