buildozer does not sort external dependencies in deps

Given this input:

deps = [
"@b",
"@a",
"//src/b",
"//src/a",
],

Buildozer will generate:

deps = [
"//src/a",
"//src/b",
"@b",
"@a",
],

is there a reason that the external dependencies are not sorted? This is in a cc_test rule.