import re


def is_stable_version(version):
    """
    Return true if version is stable, i.e. with letters in the final component.

    Stable version examples: ``1.2``, ``1.3.4``, ``1.0.5``.
    Non-stable version examples: ``1.3.4beta``, ``0.1.0rc1``, ``3.0.0dev0``.
    """
    if not isinstance(version, tuple):
        version = version.split('.')
    last_part = version[-1]

    if not re.search(r'[a-zA-Z]', last_part):
        return True
    else:
        return False