def calculate_delta_date(literal):
mapping = {<EOL>"<STR_LIT>": <NUM_LIT:0>,<EOL>"<STR_LIT>": <NUM_LIT:1>,<EOL>"<STR_LIT>": <NUM_LIT:7>,<EOL>"<STR_LIT>": <NUM_LIT:30>,<EOL>"<STR_LIT>": <NUM_LIT>,<EOL>}<EOL>today = DateTime(DateTime().Date())  <EOL>return today - mapping.get(literal, <NUM_LIT:0>)<EOL>
Calculate the date in the past from the given literal
    :param literal: A date literal, e.g. "today"
    :type literal: str
    :returns: Date between the literal and today
    :rtype: DateTime