You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: build.rs
    path of file: ./repos/pyo3/pyo3-ffi
    
    the code of the file until where you have to start completion: use pyo3_build_config::{
    bail, ensure, print_feature_cfgs,
    pyo3_build_script_impl::{
        cargo_env_var, env_var, errors::Result, is_linking_libpython, resolve_interpreter_config,
        InterpreterConfig, PythonVersion,
    },
    PythonImplementation,
};

/// Minimum Python version PyO3 supports.
struct SupportedVersions {
    min: PythonVersion,
    max: PythonVersion,
}

const SUPPORTED_VERSIONS_CPYTHON: SupportedVersions = SupportedVersions {
    min: PythonVersion { major: 3, minor: 7 },
    max: PythonVersion {
        major: 3,
        minor: 12,
    },
};

const SUPPORTED_VERSIONS_PYPY: SupportedVersions = SupportedVersions {
    min: PythonVersion { major: 3,
    
fn ensure_target_pointer_width(interpreter_config: &InterpreterConfig) -> Result<()> {
    if let Some(pointer_width) = interpreter_config.pointer_width {
        // Try to check whether the target architecture matches the python library
        let rust_target = match cargo_env_var("CARGO_CFG_TARGET_POINTER_WIDTH")
            .unwrap()
            .as_str()
        {
            "64" => 64,
            "32" => 32,
            x => bail!("unexpected Rust target pointer width: {}", x),
        };

        ensure!(
            rust_target == pointer_width,
            "your Rust target architecture ({}-bit) does not match your python interpreter ({}-bit)",
            rust_target,
            pointer_width
        );
    }
    Ok(())
}