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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def str_endswith(arr, pat, na=np.nan):
 """ Test if the end of each string element matches a pattern. Equivalent to :meth:`str.endswith`. Parameters pat : str Character sequence. Regular expressions are not accepted. na : object, default NaN Object shown if element tested is not a string. Returns ------- Series or Index of bool A Series of booleans indicating whether the given pattern matches the end of each string element. See Also -------- str.endswith : Python standard library string method. Series.str.startswith : Same as endswith, but tests the start of string. Series.str.contains : Tests if string element contains a pattern. Examples -------- 0 bat 1 bear 2 caT 3 NaN dtype: object 0 True 1 False 2 False 3 NaN dtype: object Specifying `na` to be `False` instead of `NaN`. 0 True 1 False 2 False 3 False dtype: bool """

    f = lambda x: x.endswith(pat)
    return _na_map(f, arr, na, dtype=bool)