Zstride=1. / spatial_scale, eroDivisionError: float division by zero

[13070151771]

class single_scale_rpn_outputs(nn.Module):
"""Add RPN outputs to a single scale model (i.e., no FPN)."""
def init(self, dim_in, spatial_scale):
super(single_scale_rpn_outputs,self).init()
self.dim_in = dim_in
self.dim_out = dim_in if cfg.RPN.OUT_DIM_AS_IN_DIM else cfg.RPN.OUT_DIM
anchors = generate_anchors(
stride=1. / spatial_scale,
sizes=cfg.RPN.SIZES,
aspect_ratios=cfg.RPN.ASPECT_RATIOS)
num_anchors = anchors.shape[0]

its faster-rcnn in python2.7，

stride=1. / spatial_scale,
ZeroDivisionError: float division by zero

but in python3 It can run well

what can i do。555555555