import re


def is_measurement(word):
    """
    is_measurement()

    Purpose: Checks if the word is a measurement.

    @param word. A string.
    @return      the matched object if it is a measurement, otherwise None.

    >>> is_measurement('10units') is not None
    True
    >>> is_measurement('7 units') is not None
    True
    >>> is_measurement('10cc') is not None
    True
    >>> is_measurement('300 L') is not None
    True
    >>> is_measurement('20mL') is not None
    True
    >>> is_measurement('400000 dL') is not None
    True
    >>> is_measurement('30000') is not None
    False
    >>> is_measurement('20dl') is not None
    False
    >>> is_measurement('units') is not None
    True
    """
    regex = r"^[0-9]*( )?(unit(s)|cc|L|mL|dL)$"
    return re.search(regex, word)