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Co-authored-by: Nicola Soranzo <[email protected]>

lib/galaxy/datatypes/sniff.py

@@ -598,20 +598,18 @@ def search(self, pattern):
     def search_str(self, query_str):
         return query_str in self.contents_header
 
-    def unpack_header(self, pattern):
+    def magic_header(self, pattern):
+        """
+        Unpack header and get first element
+        """
         size = struct.calcsize(pattern)
-        header_bytes = self.contents_header_bytes[0:size]
+        header_bytes = self.contents_header_bytes[:size]
         if len(header_bytes) < size:
             return None
-        return struct.unpack(pattern, header_bytes)
-
-    def magic_header(self, pattern):
-        # unpack header and get first element
-        unpacked = self.unpack_header(pattern)
-        return None if not unpacked else unpacked[0]
+        return struct.unpack(pattern, header_bytes)[0]
 
     def startswith_bytes(self, test_bytes):
-        return self.contents_header_bytes[0:len(test_bytes)] == test_bytes
+        return self.contents_header_bytes.startswith(test_bytes)
 
 
 def build_sniff_from_prefix(klass):