How do I solve a DynamicSystems error when i creat custom Component in Maple?

I am learning to use MapleSim to do my research.

and I should create a custom Component. Its function is:

there are two inputs s1 and s2, the output F=0 when s1=0, and F=s2 when s1=1.

I made a function like the figure as follows and the error occured

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params := [ ]

initialconditions := [ ]

sys := DynamicSystems [ DiffEquation]( eq, inputvariable = [s1, s2],outputvariable = [F(t)])

Error, (in DynamicSystems:-DiffEquation) unrecognized diff-equation type: 9

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anyone could help me to solve this problem.thinks