code: def grow_use_function(self, depth=0):
          "Select either function or terminal in grow method"
          if depth == 0:
              return False
          if depth == self._depth:
              return True
          return np.random.random() < 0.f grow_use_function(self, depth=0):
          "Select either function or terminal in grow method"
          if depth == 0:
              return False
          if depth == self._depth:
              return True
          return np.random.random() < 0.5
docs: Select either function or terminal in grow method