How to add suppression to custom buildStep

class CompileCore(steps.Compile):
  suppressions = [
    [ None, ".* Warning: Linking the executable .* against .*", None, None ],
    [ None, ".* Warning: Linking the shared library .* against .*", None, None ],
  ]
 
  def start(self):
    # add suppressions here
    self.addSuppression(CompileCore.suppressions)
    super(CompileCore, self).start()
 
class TestCore(steps.Test):
  suppressions = [
    [ None, "Warning: .*", None, None ],
  ]
 
  def start(self):
    # add suppressions here
    self.addSuppression(TestCore.suppressions)
    super(TestCore, self).start()

cc @cmouse