Add missing import

Former-commit-id: 159be57b6c3a77272abeab8f480cdc7e32fac998

core/processor.py

@@ -10,6 +10,8 @@ from core.io.writer import Writer
 from core.io.signal import Signal
 
 from core.cells import Cells
+from postprocessor.core.processes.merger import mergerParameters, merger
+from postprocessor.core.processes.picker import pickerParameters, picker
 
 
 class PostProcessorParameters(ParametersABC):