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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def apply_ir_heuristics(irs, node):
 """ Apply a set of heuristic to improve slithIR """


    irs = integrate_value_gas(irs)

    irs = propagate_type_and_convert_call(irs, node)
    irs = remove_unused(irs)
    find_references_origin(irs)


    return irs