diff --git a/pytransifex/api.py b/pytransifex/api.py
index fd4ee90..ebf2798 100644
--- a/pytransifex/api.py
+++ b/pytransifex/api.py
@@ -84,12 +84,14 @@ def get_project(self, project_slug: str) -> None | Resource:
                 return None
 
     @ensure_login
-    def list_resources(self, project_slug: str) -> list[Resource]:
+    def list_resources(self, project_slug: str) -> list[Any]:
         """List all resources for the project passed as argument"""
-        if self.projects:
-            res = self.projects.filter(slug=project_slug)
-            logging.info("Obtained these resources:")
-            return res
+        if project := self.get_project(project_slug=project_slug):
+            if resources := project.fetch("resources"):
+                return list(resources.all())
+            else:
+                return []
+
         raise Exception(
             f"Unable to find any project under this organization: '{self.organization}'"
         )
@@ -109,8 +111,8 @@ def create_resource(
         if project := self.get_project(project_slug=project_slug):
             resource = tx_api.Resource.create(
                 project=project,
-                name=resource_name,
-                slug=resource_slug,
+                name=resource_name or resource_slug,
+                slug=resource_slug or resource_name,
                 i18n_format=tx_api.I18nFormat(id=self.i18n_type),
             )
 
@@ -305,7 +307,7 @@ def push(
             logging.info(f"Slug: {slug}. Resources: {resources}.")
             if not slug in resources:
                 logging.info(
-                    f"{project_slug} is missing {slug}. Created it from {path}."
+                    f"{project_slug} is missing {slug}. Creating it from {path}."
                 )
                 self.create_resource(
                     project_slug=project_slug, path_to_file=path, resource_slug=slug
diff --git a/pytransifex/utils.py b/pytransifex/utils.py
index f125295..ea28b14 100644
--- a/pytransifex/utils.py
+++ b/pytransifex/utils.py
@@ -19,16 +19,16 @@ def concurrently(
     args: list[Any] | None = None,
     partials: list[Any] | None = None,
 ) -> list[Any]:
-    if args and len(args) == 0:
-        return []
-    if partials and len(partials) == 0:
-        return []
 
     with ThreadPoolExecutor() as pool:
-        if partials:
+        if not partials is None:
+            assert args is None and fn is None
             futures = [pool.submit(p) for p in partials]
-        elif fn and args:
+        elif (not args is None) and (not fn is None):
+            assert partials is None
             futures = [pool.submit(fn, *a) for a in args]
         else:
-            raise Exception("Either partials or fn and args!")
+            raise ValueError(
+                "Exactly 1 of 'partials' or 'args' must be defined. Found neither was when calling concurrently."
+            )
         return [f.result() for f in as_completed(futures)]