docs: def find_or_build(cls, **kwargs):
          """Checks if an instance already exists in db with these kwargs else
          returns a new, saved instance of the service's model class.
  
          Args:
              **kwargs: instance parameters
          """
          keys = kwargs.pop('keys') if 'keys' in kwargs else []
          return cls.first(**subdict(kwargs, keys)) or cls.build(**kwargs)