diff --git a/clearml/backend_api/session/defs.py b/clearml/backend_api/session/defs.py
index e34da8ca..674a2512 100644
--- a/clearml/backend_api/session/defs.py
+++ b/clearml/backend_api/session/defs.py
@@ -30,7 +30,7 @@ ENV_API_DEFAULT_REQ_METHOD = EnvEntry("CLEARML_API_DEFAULT_REQ_METHOD")
 """
 Experimental option to make the SDK retry on additional error codes.
 Use a comma-separated list of integer return codes.
-NOTE: this changes behavior and might cause the experiment to wait 
+NOTE: this changes behavior and might cause the experiment to wait
 for a very long time for a non-responding or mis-configured server
 """
 ENV_API_EXTRA_RETRY_CODES = EnvEntry("CLEARML_API_EXTRA_RETRY_CODES")
diff --git a/clearml/binding/fire_bind.py b/clearml/binding/fire_bind.py
index d78e909b..d35aea8f 100644
--- a/clearml/binding/fire_bind.py
+++ b/clearml/binding/fire_bind.py
@@ -134,11 +134,11 @@ class PatchFire:
                 replaced_args = []
             for param in PatchFire.__remote_task_params[PatchFire._section_name].values():
                 if command is not None and param.type == PatchFire._command_arg_type_template % command:
-                    replaced_args.append("--" + param.name[len(command + PatchFire._args_sep) :])
+                    replaced_args.append("--" + param.name[len(command + PatchFire._args_sep):])
                     value = PatchFire.__remote_task_params_dict[param.name]
                     if len(value) > 0:
                         replaced_args.append(value)
-                if param.type == PatchFire._shared_arg_type: 
+                if param.type == PatchFire._shared_arg_type:
                     replaced_args.append("--" + param.name)
                     value = PatchFire.__remote_task_params_dict[param.name]
                     if len(value) > 0:
diff --git a/clearml/storage/cache.py b/clearml/storage/cache.py
index 72762e11..6a7c84f1 100644
--- a/clearml/storage/cache.py
+++ b/clearml/storage/cache.py
@@ -167,7 +167,7 @@ class CacheManager(object):
                 ):
                     # parse the lock filename
                     name = f.name[
-                        len(CacheManager._lockfile_prefix) : -len(
+                        len(CacheManager._lockfile_prefix):-len(
                             CacheManager._lockfile_suffix
                         )
                     ]
@@ -181,7 +181,7 @@ class CacheManager(object):
                 lock_files.pop(f.name, None)
 
             # delete old files
-            files = files[self._file_limit :]
+            files = files[self._file_limit:]
             for i, f in enumerate(files):
                 if i < self._file_limit:
                     continue
diff --git a/clearml/storage/helper.py b/clearml/storage/helper.py
index 30b0cb6a..046dc107 100644
--- a/clearml/storage/helper.py
+++ b/clearml/storage/helper.py
@@ -1831,7 +1831,6 @@ class _AzureBlobServiceStorageDriver(_Driver):
         def is_legacy(self):
             return self.__legacy
 
-
     @attrs
     class _Object(object):
         container = attrib()
@@ -1950,7 +1949,6 @@ class _AzureBlobServiceStorageDriver(_Driver):
         download_done = threading.Event()
         download_done.counter = 0
 
-
         def callback_func(current, total):
             if callback:
                 chunk = current - download_done.counter
@@ -1959,7 +1957,6 @@ class _AzureBlobServiceStorageDriver(_Driver):
             if current >= total:
                 download_done.set()
 
-
         container = obj.container
         container.blob_service.MAX_SINGLE_GET_SIZE = 5 * 1024 * 1024
         _ = container.get_blob_to_path(
diff --git a/clearml/storage/manager.py b/clearml/storage/manager.py
index f53d9127..a7029c85 100644
--- a/clearml/storage/manager.py
+++ b/clearml/storage/manager.py
@@ -249,9 +249,9 @@ class StorageManager(object):
 
     @classmethod
     def download_folder(
-        cls, remote_url, local_folder=None, match_wildcard=None, overwrite=False
+        cls, remote_url, local_folder=None, match_wildcard=None, overwrite=False, skip_zero_size_check=False
     ):
-        # type: (str, Optional[str], Optional[str], bool) -> Optional[str]
+        # type: (str, Optional[str], Optional[str], bool, bool) -> Optional[str]
         """
         Download remote folder recursively to the local machine, maintaining the sub folder structure
         from the remote storage.
@@ -271,6 +271,7 @@ class StorageManager(object):
             Example: `*.json`
         :param bool overwrite: If False, and target files exist do not download.
             If True always download the remote files. Default False.
+        :param bool skip_zero_size_check: If True no error will be raised for files with zero bytes size.
 
         :return: Target local folder
         """
diff --git a/examples/frameworks/keras/requirements.txt b/examples/frameworks/keras/requirements.txt
index 4f7fcce4..9e45a014 100644
--- a/examples/frameworks/keras/requirements.txt
+++ b/examples/frameworks/keras/requirements.txt
@@ -1,3 +1,2 @@
-Keras
 tensorflow>=2.0
 clearml
\ No newline at end of file
diff --git a/examples/frameworks/pytorch/requirements.txt b/examples/frameworks/pytorch/requirements.txt
index 3673355f..674d38c7 100644
--- a/examples/frameworks/pytorch/requirements.txt
+++ b/examples/frameworks/pytorch/requirements.txt
@@ -1,9 +1,9 @@
-matplotlib
-tensorboardX
-tensorboard>=1.14.0
-torch >= 1.1.0 ; python_version >= '3.8'
-torch <= 1.5.1 ; python_version < '3.8'
-torchvision
-tqdm
-jsonschema==3.2.0 ; python_version <= '3.5'
 clearml
+jsonschema==3.2.0 ; python_version <= '3.5'
+matplotlib
+pytorch-ignite
+tensorboard>=1.14.0
+tensorboardX
+torch>=1.1.0
+torchvision>=0.3.0
+tqdm