&lt;: Real} &lt;: AbstractMeltRate 
    α  :: T
    ρi :: T
    ρw :: T
end</code></pre><p>In this case, the parameters are: a normalization coefficient <span>$\alpha$</span>, and the denisities of ice and ocean, <span>$\rho_i$</span> and <span>$\rho_w$</span>, respectively. </p><p>Now we define our &quot;constructor&quot;, a function that defines how to create one of these structures:</p><pre><code class="language-julia hljs">MISMIPMeltRateOne(; α = 1.0, ρi = 918.0, ρw = 1028.0) = MISMIPMeltRateOne(�