code: def forward(self, input):
      out = paddle.matmul(input, self.weight)
      out = out + self.bias
      return out
  
imports: from __future__ import absolute_import
  from __future__ import print_function
  from __future__ import division
  import math
  import paddle
  import paddle.nn
  import paddle.nn.functional
  from paddleseg.cvlibs import param_init
  from paddlepanseg.models.param_init import THLinearInitMixin
  from paddlepanseg.utils import use_custom_op
label_desc: Use image node_id 2 for calling the LinearWithFrozenBias obj's underlying member method code with example usage: obj.forward(input) and returns: out