address @jbweston's remarks

Author: basnijholt

adaptive/learner/sequence_learner.py

@@ -1,12 +1,9 @@
-import sys
 from copy import copy
 
 from sortedcontainers import SortedSet, SortedDict
 
 from adaptive.learner.base_learner import BaseLearner
 
-inf = sys.float_info.max
-
 
 class _IgnoreFirstArgument:
     """Remove the first argument from the call signature.
@@ -33,7 +30,8 @@ def __setstate__(self, function):
 
 
 class SequenceLearner(BaseLearner):
-    r"""A learner that will learn a sequence.
+    r"""A learner that will learn a sequence. It simply returns
+    the points in the provided sequence when asked.
 
     This is useful when your problem cannot be formulated in terms of
     another adaptive learner, but you still want to use Adaptive's