Update app.py

app.py

@@ -78,7 +78,7 @@ def transformer_encoder(inputs, head_size, num_heads, ff_dim, dropout=0):
     return LayerNormalization(epsilon=1e-6)(x + res)
 
 # RL Environment
-class PricingEnv(Env):
+class PricingEnv(gym.Env):
     def __init__(self, data):
         super(PricingEnv, self).__init__()
         self.data = data