learn_bazel/py_project/BUILD.bazel

py_library(
    name = "calculator",
    srcs = ["calculator.py"],
    # visibility
    visibility = ["//visibility:public"],
)

py_test(
    name = "calculator_test",
    srcs = ["calculator_test.py"],
    deps = [
        # These are dependencies spelled out as targets?
        "//py_project:calculator",
    ],
)