list or vector abstract data type to avoid confusionwe will use the term list to refer to the data type provided by python and use the terms general list or list structure when referring to the more general list structure as defined earlier the date abstract data type an abstract data type is defined by specifying the domain of the data elements that compose the adt and the set of operations that can be performed on that domain the definition should provide clear description of the adt including both its domain and each of its operations as only those operations specified can be performed on an instance of the adt nextwe provide the definition of simple abstract data type for representing date in the proleptic gregorian calendar defining the adt the gregorian calendar was introduced in the year by pope gregory xiii to replace the julian calendar the new calendar corrected for the miscalculation of the lunar year and introduced the leap year the official first date of the gregorian calendar is fridayoctober the proleptic gregorian calendar is an extension for accommodating earlier dates with the first date on november bc this extension simplifies the handling of dates across older calendars and its use can be found in many software applications define date adt date represents single day in the proleptic gregorian calendar in which the first day starts on november bc datemonthdayyear )creates new date instance initialized to the given gregorian date which must be valid year bc and earlier are indicated by negative year components day()returns the gregorian day number of this date month()returns the gregorian month number of this date year()returns the gregorian year of this date monthname()returns the gregorian month name of this date dayofweek()returns the day of the week as number between and with representing monday and representing sunday numdaysotherdate )returns the number of days as positive integer between this date and the otherdate isleapyear()determines if this date falls in leap year and returns the appropriate boolean value