3.7.0 (v3.7.0:1bf9cc5093, Jun 26 2018, 23:26:24) 
[Clang 6.0 (clang-600.0.57)]
Python Type "help", "copyright", "credits" or "license" for more information.
str(3: object)
Traceback (most recent call last):
  Python Shell, prompt 1, line 1
Syntax Error: invalid syntax: <string>, line 1, pos 6
str(3)
'3'
s = 'csc120        '
s
'csc120        '
s.rstrip()
'csc120'
s = 'csc1201111111111'
s.rstrip(['1': str])
Traceback (most recent call last):
  Python Shell, prompt 7, line 1
Syntax Error: invalid syntax: <string>, line 1, pos 14
s.rstrip(['1': str]) # square brackets mean it's an optional argument
Traceback (most recent call last):
  Python Shell, prompt 8, line 1
Syntax Error: invalid syntax: <string>, line 1, pos 14
s.rstrip('1')
'csc120'
s.count('c')
2
s.count(sub: str, 2)
Traceback (most recent call last):
  Python Shell, prompt 11, line 1
Syntax Error: invalid syntax: <string>, line 1, pos 12
s.count('c', 2)
1
S.count('c', 2, 3)
Traceback (most recent call last):
  Python Shell, prompt 13, line 1
builtins.NameError: name 'S' is not defined
s.count('c', 2, 3)
1
# do NOT include square brackets in your function calls
# or colons