Define a Custom Probability Distribution - Maple Programming Help

 > $U≔\mathrm{Statistics}\left[\mathrm{Distribution}\right]\left(\mathrm{PDF}=\left({t}{\to }{\mathrm{piecewise}}\left({t}{<}{0}{,}{0}{,}{t}{<}{3}{,}\frac{{1}}{{3}}{,}{0}\right)\right)\right):$