Returns a list of words that occur in the text. Eliminates stopwords.

def eliminate_repeats(text):
    '''Returns a list of words that occur in the text. Eliminates stopwords.'''
    
    bannedwords = read_file('stopwords.txt')
    alphabet = 'abcdefghijklmnopqrstuvwxyz'
    words = text.split()
    standardwords = []
    for word in words:
        newstr = ''
        for char in word:
            if char in alphabet or char in alphabet.upper():
               newstr += char
        if newstr not in standardwords and newstr != '' and newstr not in bannedwords:
            standardwords.append(newstr)
        
    return map(lambda x: x.lower(),standardwords)