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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 _ValidateCacheFileMetadataHeader(self, cache_file_metadata_header):
 """Determines whether the cache file metadata header is valid. Args: cache_file_metadata_header (firefox_cache2_file_metadata_header):
 cache file metadata header. Returns: bool: True if the cache file metadata header is valid. """

    # TODO: add support for format version 2 and 3
    return (
        cache_file_metadata_header.key_size > 0 and
        cache_file_metadata_header.key_size < self._MAXIMUM_URL_LENGTH and
        cache_file_metadata_header.format_version == 1 and
        cache_file_metadata_header.last_fetched_time > 0 and
        cache_file_metadata_header.fetch_count > 0)