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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def singularize(plural):
 """Convert plural word to its singular form. Args: plural: A word in its plural form. Returns: The word in its singular form. """

    if plural in UNCOUNTABLES:
        return plural
    for i in IRREGULAR:
        if i[1] == plural:
            return i[0]
    for i in SINGULARIZE_PATTERNS:
        if re.search(i[0], plural):
            return re.sub(i[0], i[1], plural)
    return plural