parameters: (self, label=None)
docstring: Release a machine.
          @param label: machine name.
docstring_summary: Release a machine.
docstring_tokens: Release a machine .
function: def release(self, label=None):
          """Release a machine.
          @param label: machine name.
          """
          self.db.unlock_machine(label)
function_tokens: def release ( self , label = None ) : self . db . unlock_machine ( label )