Clean up callback interfaces.

service/datastore/propertytype_string.go

-// generated by stringer -type=PropertyType; DO NOT EDIT
+// Code generated by "stringer -type=PropertyType"; DO NOT EDIT
 
 package datastore
 
 import "fmt"
 
 const _PropertyType_name = "PTNullPTIntPTTimePTBoolPTBytesPTStringPTFloatPTGeoPointPTKeyPTBlobKeyPTUnknown"
 
 var _PropertyType_index = [...]uint8{0, 6, 11, 17, 23, 30, 38, 45, 55, 60, 69, 78}
 
 func (i PropertyType) String() string {
         if i >= PropertyType(len(_PropertyType_index)-1) {
                 return fmt.Sprintf("PropertyType(%d)", i)
         }
         return _PropertyType_name[_PropertyType_index[i]:_PropertyType_index[i+1]]
 }