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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 replace(obj, **changes):
 """Return a new object replacing specified fields with new values. This is especially useful for frozen classes. Example usage: @dataclass(frozen=True) class C: x: int y: int c = C(1, 2) c1 = replace(c, x=3) assert c1.x == 3 and c1.y == 2 """


    # We're going to mutate 'changes', but that's okay because it's a
    # new dict, even if called with 'replace(obj, **my_changes)'.

    if not _is_dataclass_instance(obj):
        raise TypeError("replace() should be called on dataclass instances")

    # It's an error to have init=False fields in 'changes'.
    # If a field is not in 'changes', read its value from the provided obj.

    for f in getattr(obj, _FIELDS).values():
        if not f.init:
            # Error if this field is specified in changes.
            if f.name in changes:
                raise ValueError(f'field {f.name} is declared with '
                                 'init=False, it cannot be specified with '
                                 'replace()')
            continue

        if f.name not in changes:
            changes[f.name] = getattr(obj, f.name)

    # Create the new object, which calls __init__() and
    # __post_init__() (if defined), using all of the init fields we've
    # added and/or left in 'changes'.  If there are values supplied in
    # changes that aren't fields, this will correctly raise a
    # TypeError.
    return obj.__class__(**changes)