Capitalizes the first letter of a string.

Capitalize the first letter of the string and then add it with rest of the string.
Omit the lower_rest parameter to keep the rest of the string intact, or set it to True to convert to lowercase.


def capitalize(s, lower_rest=False):
  return s[:1].upper() + (s[1:].lower() if lower_rest else s[1:])


capitalize('fooBar') # 'FooBar'
capitalize('fooBar', True) # 'Foobar'