Create a program that can compute the required cement, sand and gravel based on a given volume of a specific concrete class type using conditional statements. Use python codes.

TABLE $1-2$ CONCRETE PROPORTION

$\backslash$table$[[$CLASS$,$MIXTURE,CEMENT,$\backslash$table$[[$SAND$],[$cu$.$ m$.]],\backslash$table$[[$GRAVEL$],[$cu$.$ m$.]]],[40$ kg$./$bag$,50k\frac{g}{\frac{?}{?}}$bag