diff --git a/bin/pick/core.py b/bin/pick/core.py
index 766749c471f..d805a7be987 100644
--- a/bin/pick/core.py
+++ b/bin/pick/core.py
@@ -42,7 +42,6 @@ if typing.TYPE_CHECKING:
         nominated: bool
         nomination_type: typing.Optional[int]
         resolution: typing.Optional[int]
-        main_sha: typing.Optional[str]
         because_sha: typing.Optional[str]
 
 IS_FIX = re.compile(r'^\s*fixes:\s*([a-f0-9]{6,40})', flags=re.MULTILINE | re.IGNORECASE)
@@ -118,7 +117,6 @@ class Commit:
     nominated: bool = attr.ib(False)
     nomination_type: typing.Optional[NominationType] = attr.ib(None)
     resolution: Resolution = attr.ib(Resolution.UNRESOLVED)
-    main_sha: typing.Optional[str] = attr.ib(None)
     because_sha: typing.Optional[str] = attr.ib(None)
 
     def to_json(self) -> 'CommitDict':
@@ -131,7 +129,7 @@ class Commit:
 
     @classmethod
     def from_json(cls, data: 'CommitDict') -> 'Commit':
-        c = cls(data['sha'], data['description'], data['nominated'], main_sha=data['main_sha'], because_sha=data['because_sha'])
+        c = cls(data['sha'], data['description'], data['nominated'], because_sha=data['because_sha'])
         if data['nomination_type'] is not None:
             c.nomination_type = NominationType(data['nomination_type'])
         if data['resolution'] is not None: