Retrieve a list of file keys that have been read into the database.

        This is a utility method that can be used to programmatically access the GsshaPy file objects. Use these keys
        in conjunction with the dictionary returned by the getFileObjects method.

        Returns:
            list: List of keys representing file objects that have been read into the database.

def getFileKeys(self):
        """
        Retrieve a list of file keys that have been read into the database.

        This is a utility method that can be used to programmatically access the GsshaPy file objects. Use these keys
        in conjunction with the dictionary returned by the getFileObjects method.

        Returns:
            list: List of keys representing file objects that have been read into the database.
        """
        files = self.getFileObjects()

        files_list = []

        for key, value in files.iteritems():
            if value:
                files_list.append(key)

        return files_list