diff --git a/nnabla_rl/__init__.py b/nnabla_rl/__init__.py
index 20806c2f..bd9971ee 100644
--- a/nnabla_rl/__init__.py
+++ b/nnabla_rl/__init__.py
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-__version__ = '0.14.0.dev1'
+__version__ = '0.15.0.dev1'
 
 from nnabla_rl.logger import enable_logging, disable_logging  # noqa
 from nnabla_rl.scopes import eval_scope, is_eval_scope  # noqa
diff --git a/nnabla_rl/models/pybullet/q_functions.py b/nnabla_rl/models/pybullet/q_functions.py
index 6157e7c6..98ccc942 100644
--- a/nnabla_rl/models/pybullet/q_functions.py
+++ b/nnabla_rl/models/pybullet/q_functions.py
@@ -107,7 +107,7 @@ def argmax_q(self, s: Tuple[nn.Variable, nn.Variable]) -> nn.Variable:
         def objective_function(a: nn.Variable) -> nn.Variable:
             batch_size, sample_size, action_dim = a.shape
             a = a.reshape((batch_size*sample_size, action_dim))
-            q_value = self.q(tiled_s, a)  # type: ignore
+            q_value = self.q(tiled_s, a)
             q_value = q_value.reshape((batch_size, sample_size, 1))
             return q_value