Resolve "release v1.2.0"

Closes #257 (closed)

mlair/helpers/helpers.py

@@ -18,7 +18,7 @@ def to_list(obj: Any) -> List:
 
     :return: list containing obj, or obj itself (if obj was already a list)
     """
-    if isinstance(obj, set):
+    if isinstance(obj, (set, tuple)):
         obj = list(obj)
     elif not isinstance(obj, list):
         obj = [obj]
@@ -116,6 +116,12 @@ def select_from_dict(dict_obj: dict, sel_list: Any):
 
 def extract_value(encapsulated_value):
     try:
-        return extract_value(encapsulated_value[0])
+        if isinstance(encapsulated_value, str):
+            raise TypeError
+        if len(encapsulated_value) == 1:
+            return extract_value(encapsulated_value[0])
+        else:
+            raise NotImplementedError("Trying to extract an encapsulated value from objects with more than a single "
+                                      "entry is not supported by this function.")
     except TypeError:
         return encapsulated_value