>>> test = '8765iouy9987OIUY'
>>> test.islower()
False
>>> test.isupper()
False

>>> test2 = 'b1'
>>> test2.islower()
True
>>> test2.isupper()
False

>>> test = '8765iouy9987OIUY'
>>> any(c.islower() for c in test)
True
>>> any(c.isupper() for c in test)
True

>>> test = '8765iouy9987OIUY'
>>> "".join([i for i in test if not i.islower()])
'87659987OIUY'

import re
print re.findall(r"[a-z]",'8765iouy9987OIUY')

['i', 'o', 'u', 'y']

map(str.isupper, '8765iouy9987OIUY')
# output: [False, False, False, False, False, False, False, False,
#         False, False, False, False, True, True, True, True]

any(map(str.isupper, '8765iouy9987OIUY'))
# output: True