old_contents: # Copyright (c) 2021 The Regents of The University of California
  # All rights reserved.
  #
  # Redistribution and use in source and binary forms, with or without
  # modification, are permitted provided that the following conditions are
  # met: redistributions of source code must retain the above copyright
  # notice, this list of conditions and the following disclaimer;
  # redistributions in binary form must reproduce the above copyright
  # notice, this list of conditions and the following disclaimer in the
  # documentation and/or other materials provided with the distribution;
  # neither the name of the copyright holders nor the names of its
  # contributors may be used to endorse or promote products derived from
  # this software without specific prior written permission.
  #
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  from datetime import datetime
  from typing import Dict, List, Optional, Union
  
  from .jsonserializable import JsonSerializable
  from .group import Group
  from .statistic import Statistic
  from .timeconversion import TimeConversion
  
  class SimStat(JsonSerializable):
      """
      Contains all the statistics for a given simulation.
      """
  
      creation_time: Optional[datetime]
      time_conversion: Optional[TimeConversion]
      simulated_begin_time: Optional[Union[int, float]]
      simulated_end_time: Optional[Union[int, float]]
  
      def __init__(self, creation_time: Optional[datetime],
                   time_conversion: Optional[TimeConversion],
                   simulated_begin_time: Optional[Union[int, float]],
                   simulated_end_time: Optional[Union[int, float]],
                   **kwargs: Dict[str, Union[Group,Statistic,List[Group]]]):
          self.creation_time = creation_time
          self.time_conversion = time_conversion
          self.simulated_begin_time = simulated_begin_time
          self.simulated_end_time = simulated_end_time
  
          for key,value in kwargs.items():
              setattr(self, key, value)
new_contents: # Copyright (c) 2021 The Regents of The University of California
  # All rights reserved.
  #
  # Redistribution and use in source and binary forms, with or without
  # modification, are permitted provided that the following conditions are
  # met: redistributions of source code must retain the above copyright
  # notice, this list of conditions and the following disclaimer;
  # redistributions in binary form must reproduce the above copyright
  # notice, this list of conditions and the following disclaimer in the
  # documentation and/or other materials provided with the distribution;
  # neither the name of the copyright holders nor the names of its
  # contributors may be used to endorse or promote products derived from
  # this software without specific prior written permission.
  #
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  from datetime import datetime
  from typing import Dict, List, Optional, Union
  
  from .jsonserializable import JsonSerializable
  from .group import Group
  from .statistic import Statistic
  from .timeconversion import TimeConversion
  
  class SimStat(JsonSerializable):
      """
      Contains all the statistics for a given simulation.
      """
  
      creation_time: Optional[datetime]
      time_conversion: Optional[TimeConversion]
      simulated_begin_time: Optional[Union[int, float]]
      simulated_end_time: Optional[Union[int, float]]
  
      def __init__(self, creation_time: Optional[datetime] = None,
                   time_conversion: Optional[TimeConversion] = None,
                   simulated_begin_time: Optional[Union[int, float]] = None,
                   simulated_end_time: Optional[Union[int, float]] = None,
                   **kwargs: Dict[str, Union[Group,Statistic,List[Group]]]):
          self.creation_time = creation_time
          self.time_conversion = time_conversion
          self.simulated_begin_time = simulated_begin_time
          self.simulated_end_time = simulated_end_time
  
          for key,value in kwargs.items():
              setattr(self, key, value)
subject: Fix optional parameters with default None