update comment

Author: Hsuxu

FocalLoss/focal_loss.py

@@ -9,7 +9,6 @@ class BinaryFocalLoss(nn.Module):
     This is a implementation of Focal Loss with smooth label cross entropy supported which is proposed in
     'Focal Loss for Dense Object Detection. (https://arxiv.org/abs/1708.02002)'
         Focal_Loss= -1*alpha*(1-pt)*log(pt)
-    :param num_class:
     :param alpha: (tensor) 3D or 4D the scalar factor for this criterion
     :param gamma: (float,double) gamma > 0 reduces the relative loss for well-classified examples (p>0.5) putting more
                     focus on hard misclassified example