def to_mutable
    each_with_object( {} ) { |(key, value), hash|
      hash[ Hamster.to_mutable key ] = Hamster.to_mutable value
    }
  end
def to_mutable
    each_with_object( {} ) { |(key, value), hash|
      hash[ Hamster.to_mutable key ] = Hamster.to_mutable value
    }
  end
Instance Methods
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