vars() can't be used in list interpretation?

[Cheng]

P.S. I am not sure why this the interpreter in this site does not recognize vars()... however, it appears that the interpreter in W3Schools works just fine with vars.

I am using vars() and globals(). I am not sure whether this is a good practice, do let me know if it isn't!
This works

x=10
y=5
xy_wsp = [('x','x'),('y','y')]
lst = [lv for v,lv in xy_wsp]
vars()[lst[0]]

For-looping it,

new_lst = []
for lv in lst:
    new_lst.append(vars()[lv])

However, if I use in a list interpretation,

[vars()[lv] for lv in lst]

Then I get

Error:
KeyError: 'x'

Somehow,

[globals()[lv] for lv in lst]

works.

Any idea why? Thanks in advance!