import string


def get_character_type(character):
    """
    >>> get_character_type('a')
    'alpha'
    >>> get_character_type('1')
    'numeric'
    >>> get_character_type('.')
    'punctuation'
    >>> get_character_type(' ')
    """
    if character.isalpha():
        return 'alpha'
    elif character.isnumeric():
        return 'numeric'
    elif character in string.punctuation:
        return 'punctuation'
    return None