When the argument to lstrip / strip has a number and it matches the string it begins to act different. 

>>> text = "apiv1appliance"
>>> text.strip("apiv1")
'liance'
>>> text.strip("apiv2")
'1appliance'
>>> text.strip("a")
'piv1appliance'
>>> text.strip("ap")
'iv1appliance'
>>> text.strip("api")
'v1appliance'
>>> text.strip("apiv")
'1appliance'
>>> text.strip("apiv1")
'liance'
>>> text.strip("apiv2")
'1appliance'