def []=(key, value)
      coerced_value = coercion(key).present? ? coercion(key).call(value) : value
      old_setter(key, coerced_value)
    end
def []=(key, value)
      coerced_value = coercion(key).present? ? coercion(key).call(value) : value
      old_setter(key, coerced_value)
    end
Override setter to coerce the given value if a coercion is defined