import re


def _find_word(input):
    """
    _find_word - function to find words in the input sentence
    Inputs:
        - input : string
	    Input sentence
    Outputs:
        - words : list
	    List of words
        - tags : list
            List of pos tags
    """
    # split by whitespace
    input = re.split(pattern = '[\s]+', string = input)

    # find words in WORD_POS pattern
    valid_word = lambda x: True if re.findall(pattern = r'[a-zA-Z]*_[a-zA-Z]*', string = x) else False
    words = []
    tags = []
    for token in input:
    	if valid_word(token):
            word, pos = token.split('_')
            words.append(word)
            tags.append(pos)

    return words, tags