example from command line:

'_element_no_of_hsscch'.lstrip('_element_')
'o_of_hsscch'
'_element_o_of_hsscch'.lstrip('_element_')
'o_of_hsscch'

What did you expect? Quoting from the docs,

"""The chars argument is not a prefix; rather, all combinations of its
values are stripped:

>>> 'www.example.com'.lstrip('cmowz.')
'example.com'
"""

print '_element_no_of_hsscch'.lstrip.__doc__
S.lstrip([chars]) -> string or unicode

Return a copy of the string S with leading whitespace removed.
If chars is given and not None, remove characters in chars instead.
If chars is unicode, S will be converted to unicode before stripping

Ok, I didn't understand it correctly, because i red only __doc__ from
which is not the functionality clear. I found a workaround for it...

Let's leave it closed.