from __future__ import (absolute_import, division, print_function)

from .py3compat import viewitems


def dict_keys_to_upper(d):
    """Return a dictionary with the keys changed to uppercase.

    Args:

        d (:obj:`dict`): A dictionary.

    Returns:

        :obj:`dict`: A dictionary with uppercase keys.

    """
    return {key.upper(): val for key, val in viewitems(d)}