Markus Holzer
--- a/lbmpy/macroscopic_value_kernels.py
+++ b/lbmpy/macroscopic_value_kernels.py

    eqs = cqc.output_equations_from_pdfs(pdf_symbols, output_mapping).all_assignments

-    if target == 'cpu':
+    if target == Target.CPU:
        import pystencils.cpu as cpu
        kernel = cpu.make_python_function(cpu.create_kernel(
            eqs, ghost_layers=ghost_layers, iteration_slice=iteration_slice))
-    elif target == 'gpu':
+    elif target == Target.GPU:
        import pystencils.gpucuda as gpu
        kernel = gpu.make_python_function(gpu.create_cuda_kernel(
            eqs, ghost_layers=ghost_layers, iteration_slice=iteration_slice))
    else:
-        raise ValueError("Unknown target '%s'. Possible targets are 'cpu' and 'gpu'" % (target,))
+        raise ValueError("Unknown target '%s'. Possible targets are `Target.CPU` and `Target.GPU`" % (target,))