remove BaseLearner import to avoid circular import

Author: basnijholt

adaptive/utils.py

@@ -9,8 +9,6 @@
 
 from atomicwrites import AtomicWriter
 
-from adaptive.learner.base_learner import BaseLearner
-
 
 def named_product(**items):
     names = items.keys()
@@ -72,7 +70,7 @@ def decorator(method):
 
 
 class _RequireAttrsABCMeta(abc.ABCMeta):
-    def __call__(self, *args, **kwargs) -> BaseLearner:
+    def __call__(self, *args, **kwargs):
         obj = super().__call__(*args, **kwargs)
         for name, type_ in obj.__annotations__.items():
             try: