@staticmethod
def prepare_extra_data_map(extra_data_map):
    """Prepare extra data map.

        Replace any occurances of "dimensions." or "meta." or "value_meta."
        to "dimensions#", "meta#" or "value_meta#" in extra_data_map.

        """
    prepared_extra_data_map = {}
    for column_name in list(extra_data_map):
        column_value = extra_data_map[column_name]
        if column_name.startswith('dimensions.'):
            column_name = column_name.replace('dimensions.', 'dimensions#')
        elif column_name.startswith('meta.'):
            column_name = column_name.replace('meta.', 'meta#')
        elif column_name.startswith('value_meta.'):
            column_name = column_name.replace('value_meta.', 'value_meta#')
        elif column_name.startswith('extra_data_map.'):
            column_name = column_name.replace('extra_data_map.', '')
        prepared_extra_data_map[column_name] = column_value
    return prepared_extra_data_map
