Added deprecation decorator

src/utils/deprecated.py

@@ -0,0 +1,40 @@
+"""
+Deprecated decorator from StackOverflow:
+https://stackoverflow.com/questions/2536307/decorators-in-the-python-standard-lib-deprecated-specifically
+"""
+import warnings
+import functools
+
+
+def deprecated(reason: str = ""):
+    """This is a decorator which can be used to mark functions
+    as deprecated. It will result in a warning being emitted
+    when the function is used."""
+
+    def decorator(func):
+        @functools.wraps(func)
+        def new_func(*args, **kwargs):
+            warnings.simplefilter('always', DeprecationWarning)
+            msg = f"Call to deprecated function {func.__name__}."
+
+            if reason:
+                msg += f"\nReason: {reason}"
+
+            warnings.warn(
+                msg,
+                category=DeprecationWarning,
+                stacklevel=2
+            )
+            warnings.simplefilter('default', DeprecationWarning)
+            return func(*args, **kwargs)
+
+        return new_func
+
+    # If the decorator is called without arguments
+    if callable(reason):
+        f = reason
+        reason = ""
+        return decorator(f)
+
+    return decorator
+