diff --git a/opentelemetry-api/src/opentelemetry/trace/propagation/textmap.py b/opentelemetry-api/src/opentelemetry/trace/propagation/textmap.py
index 0960bc73bad..ec505135bec 100644
--- a/opentelemetry-api/src/opentelemetry/trace/propagation/textmap.py
+++ b/opentelemetry-api/src/opentelemetry/trace/propagation/textmap.py
@@ -34,11 +34,12 @@ def get(self, carrier: TextMapPropagatorT, key: str) -> typing.List[str]:
         or more values from the carrier. In the case that
         the value does not exist, returns an empty list.
 
-        Args: carrier: and object which contains values that are used to
-        construct a Context. This object must be paired with an appropriate
-        getter which understands how to extract a value from it.
-        key: key of a field in carrier. Returns: first value of the
-        propagation key or an empty list if the key doesn't exist.
+        Args:
+            carrier: An object which contains values that are used to
+                    construct a Context.
+            key: key of a field in carrier.
+        Returns: first value of the propagation key or an empty list if the
+                key doesn't exist.
         """
         raise NotImplementedError()
 
@@ -46,10 +47,8 @@ def keys(self, carrier: TextMapPropagatorT) -> typing.List[str]:
         """Function that can retrieve all the keys in a carrier object.
 
         Args:
-            carrier: and object which contains values that are
-                used to construct a Context. This object
-                must be paired with an appropriate getter
-                which understands how to extract a value from it.
+            carrier: An object which contains values that are
+                used to construct a Context.
         Returns:
             list of keys from the carrier.
         """
@@ -60,31 +59,15 @@ class DictGetter(Getter[typing.Dict[str, CarrierValT]]):
     def get(
         self, carrier: typing.Dict[str, CarrierValT], key: str
     ) -> typing.List[str]:
-        val = carrier.get(key, None)
-        if not val:
-            return []
-        return val if isinstance(val, typing.List) else [val]
+        val = carrier.get(key, [])
+        if isinstance(val, typing.Iterable) and not isinstance(val, str):
+            return list(val)
+        return [val]
 
     def keys(self, carrier: typing.Dict[str, CarrierValT]) -> typing.List[str]:
         return list(carrier.keys())
 
 
-class CustomGetter(Getter[TextMapPropagatorT]):
-    def __init__(
-        self,
-        get: typing.Callable[[TextMapPropagatorT, str], typing.List[str]],
-        keys: typing.Callable[[TextMapPropagatorT], typing.List[str]],
-    ):
-        self._get = get
-        self._keys = keys
-
-    def get(self, carrier: TextMapPropagatorT, key: str) -> typing.List[str]:
-        return self._get(carrier, key)
-
-    def keys(self, carrier: TextMapPropagatorT) -> typing.List[str]:
-        return self._keys(carrier)
-
-
 class TextMapPropagator(abc.ABC):
     """This class provides an interface that enables extracting and injecting
     context into headers of HTTP requests. HTTP frameworks and clients
diff --git a/opentelemetry-sdk/tests/trace/propagation/test_b3_format.py b/opentelemetry-sdk/tests/trace/propagation/test_b3_format.py
index d68ebe20d77..79c4618aee7 100644
--- a/opentelemetry-sdk/tests/trace/propagation/test_b3_format.py
+++ b/opentelemetry-sdk/tests/trace/propagation/test_b3_format.py
@@ -19,7 +19,7 @@
 import opentelemetry.sdk.trace.propagation.b3_format as b3_format
 import opentelemetry.trace as trace_api
 from opentelemetry.context import get_current
-from opentelemetry.trace.propagation.textmap import CustomGetter, DictGetter
+from opentelemetry.trace.propagation.textmap import DictGetter
 
 FORMAT = b3_format.B3Format()
 
@@ -320,13 +320,12 @@ def test_inject_empty_context():
     def test_default_span():
         """Make sure propagator does not crash when working with DefaultSpan"""
 
-        def default_span_getter(carrier, key):
-            return carrier.get(key, None)
+        class CarrierGetter(DictGetter):
+            def get(self, carrier, key):
+                return carrier.get(key, None)
 
         def setter(carrier, key, value):
             carrier[key] = value
 
-        ctx = FORMAT.extract(
-            CustomGetter(default_span_getter, DictGetter().keys), {}
-        )
+        ctx = FORMAT.extract(CarrierGetter(), {})
         FORMAT.inject(setter, {}, ctx)