import re

def get_3nums(text):
    '''Return a list of all exactly 3-digit numbers in text.'''
    return re.findall(r'\b\d{3}\b', text)


def is_int(text):
    '''Return whether text is a string representation of an integer.'''
    return re.search(r'^-?\d+$', text) != None


def is_float(text):
    '''Return whether text is a string representation of a float.'''
    return re.search(r'^-?\d+\.\d+$', text) != None


def modifier_demo():
    '''A demonstration of the quantity modifiers.'''
    text = 'cabbbb abe draw'
    print(text)
    print('+', re.findall(r'ab+', text))
    print('*', re.findall(r'ab*', text))
    print('?', re.findall(r'ab?', text))