new_contents: class IfStatement:
      def __init__(self, condition, if_body, else_body=None):
          self.condition = condition
          self.if_body = if_body
          self.else_body = else_body
          
      def eval(self, env):
          if self.condition.eval(env):
              self.if_body.eval(env)
          elif self.else_body is not None:
              if not self.condition.eval(env):
                  self.else_body.eval(env)
              
      def __repr__(self):
          return "IfStatement: {0} {1}".format(self.condition, self.body)
  
subject: Create ifstatement.py