In typeCheck() (the incomplete hand-rolled checker), implemented the cases for Sigma types.
In typeCheck() (the incomplete hand-rolled checker), implemented the cases for Sigma types.

rocketnia/era-cene,rocketnia/era-cene,rocketnia/era,era-platform/cene,era-platform/cene,rocketnia/era-cene,rocketnia/era,era-platform/cene,rocketnia/era