title: AttributeError: module 'keras.utils' has no attribute 'get_file' using segmentation_models
body: <p>I'm trying to use segmentation models but I can't fix this error. I've searched for this particular
  one but couldn't find an answer. I'm using pycharm and this error is linked to this specific line of code
  BACKBONE = 'resnet34'</p>
  <pre><code>model1 = sm.Unet(BACKBONE, weights=None,
                   encoder_weights='imagenet',
                   classes=num_classes,
                   activation='softmax',
                   decoder_block_type = 'upsampling') 
  </code></pre>
  <p>which is also the 83rd. I searched in the documentation and apparently the versions of tensorflow keras etc satisfy the requirements.I really don't know what to do given the fact that I really tried to install and uninstall everything in many combinations in order to get this piece of code to work.Thank you all for your help and time! Below there's the complete error, hoping it might help you!</p>
  <pre><code>    `Traceback (most recent call last):
        File &quot;C:\Users\Giulia\PycharmProjects\multiclass_new\main.py&quot;, line 83, in &lt;module&gt;
          model1 = sm.Unet('resnet34', weights=None,
        File &quot;C:\Users\Giulia\PycharmProjects\multiclass_new\venv\lib\site- 
     packages\segmentation_models\__init__.py&quot;, line 34, in wrapper
          return func(*args, **kwargs)
        File &quot;C:\Users\Giulia\PycharmProjects\multiclass_new\venv\lib\site- 
     packages\segmentation_models\models\unet.py&quot;, line 221, in Unet
          backbone = Backbones.get_backbone(
        File &quot;C:\Users\Giulia\PycharmProjects\multiclass_new\venv\lib\site- 
     packages\segmentation_models\backbones\backbones_factory.py&quot;, line 103, in get_backbone
          model = model_fn(*args, **kwargs)
        File &quot;C:\Users\Giulia\PycharmProjects\multiclass_new\venv\lib\site- 
     packages\classification_models\models_factory.py&quot;, line 78, in wrapper
          return func(*args, **new_kwargs)
        File &quot;C:\Users\Giulia\PycharmProjects\multiclass_new\venv\lib\site- 
     packages\classification_models\models\resnet.py&quot;, line 314, in ResNet34
          return ResNet(
        File &quot;C:\Users\Giulia\PycharmProjects\multiclass_new\venv\lib\site- 
     packages\classification_models\models\resnet.py&quot;, line 280, in ResNet
          load_model_weights(model, model_params.model_name,
        File &quot;C:\Users\Giulia\PycharmProjects\multiclass_new\venv\lib\site- 
     packages\classification_models\weights.py&quot;, line 25, in load_model_weights
          weights_path = keras_utils.get_file(
      AttributeError: module 'keras.utils' has no attribute 'get_file'
  </code></pre>