class_docstr: The class for implementing FCENet head.
  FCENet(CVPR2021): Fourier Contour Embedding for Arbitrary-shaped Text
  Detection.
  
  [https://arxiv.org/abs/2104.10442]
  
  Args:
      in_channels (int): The number of input channels.
      scales (list[int]) : The scale of each layer.
      fourier_degree (int) : The maximum Fourier transform degree k.
code: def forward_single(self, x):
      cls_predict = self.out_conv_cls(x)
      reg_predict = self.out_conv_reg(x)
      return cls_predict, reg_predict
  
file_path: PaddleOCR/ppocr/modeling/heads/det_fce_head.py
imports: from paddle import nn
  from paddle import ParamAttr
  import paddle.nn.functional
  from paddle.nn.initializer import Normal
  import paddle
  from functools import partial
label_desc: Use image node_id 3 for calling the FCEHead obj's underlying member method code with example usage: obj.forward_single(x) and returns: cls_predict,  reg_predict