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The function toggle_case_first(s) should return a new string where the first character's case is toggled — uppercase becomes lowercase, lowercase becomes uppercase. The rest of the string stays the same.

The function crashes immediately with a TypeError. Why can't Python do what the code is asking?

hint 2after hint 1

hint 3after hint 2

solution

Read the code. Before running anything: what does the last line below give?

def toggle_case_first(s):

"""

Returns the string with the first character's case toggled.

Uppercase becomes lowercase; lowercase becomes uppercase.

The rest of the string is unchanged.

Example: toggle_case_first("Hello") -> "hello"

"""

if s[0].isupper():

s[0] = s[0].lower()

else:

s[0] = s[0].upper()

return s

>>> toggle_case_first('Hello')