import re


def remove_user_tags(text):
    """Remove user tags such as @realDonaldTrump from text.

    Args:
        text (str): Text from which to remove links.

    Returns:
        str: The same text with user tags such as @realDonaldTrump removed.

    Notes: Regex from https://stackoverflow.com/a/6351873

    Examples:
        >>> remove_user_tags('@user test text')
        ' test text'

        >>> remove_user_tags('email@user.com')
        'email@user.com'

        >>> remove_user_tags('test text')
        'test text'
    """
    return re.sub(r"(?<=^|(?<=[^a-zA-Z0-9-_\.]))@([A-Za-z]+[A-Za-z0-9-_]+)", "", text)