code: def input_dim(self, value):
      if not isinstance(value, int) or value <= 0:
          raise ValueError(
              "Input dimension should be an integer larger than 0."
          )
      self._input_dim = value
      self._generate_matrices()
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import pytest
  import numpy
  import torch
  import torch.nn
  import torch.optim
  from torch.utils.data import Dataset, DataLoader
  import bluefog.torch
  from bluefog.common import topology_util
label_desc: Use image node_id 4 for calling the LinearProblemBuilder obj's underlying member method code with example usage: obj.input_dim(value) without return types