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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 validate(self):
 """ Validates that all required fields are present """

    if not self.start:
      raise ValueError("Event has no start date")

    if not self.end:
      raise ValueError("Event has no end date")

    if self.end < self.start:
      raise ValueError("Start date is after end date")

    if self.reminder_minutes_before_start and not isinstance(self.reminder_minutes_before_start, int):
      raise TypeError("reminder_minutes_before_start must be of type int")

    if self.is_all_day and not isinstance(self.is_all_day, bool):
      raise TypeError("is_all_day must be of type bool")