diff --git a/pipeline/adjusters.py b/pipeline/adjusters.py
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--- /dev/null
+++ b/pipeline/adjusters.py
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+"""adjusters.py -- adjust the gathered Features
+
+This is usually done to either modify to reduce the Features in some way.
+
+For example:
+
+ - TargetTimeAdjuster: drop Features until the target time is reached
+ - FeatureCountAdjuster: drop Features until the target number of Features is reached
+
+TODO: Consider eg a generic PredicateAdjuster -- supply a predicate/lambda that will be used to determine whether to keep a Feature or not.
+"""
+
+class Adjuster():
+    """Generic Adjuster class. Expects a list of Features and returns a list of Features."""
+
+    def __init__(self, features: list=[]):
+        """Initialize the Adjuster with Features.
+
+        NOTE: an empty feature list is permitted, since a FeatureExtractor may not produce features. Adjusters subclassing should be aware of this.
+        """
+        self.features = features
+
+
+    def adjust(self):
+        """Adjust the Features. Override this method in subclasses."""