def get_dir_from_zipfile(zip_file, fallback=None):
    """Return the name of the root folder in a zip file.

    :param zip_file: a :class:`zipfile.ZipFile` instance.
    :param fallback: if `None`, the name of the zip file is used. This is
        returned if the zip file contains more than one top-level directory,
        or none at all.
    """
    fallback = fallback or zip_file.filename
    directories = [name for name in zip_file.namelist() if name.endswith("/")
                   and len(PurePath(name).parts) == 1]
    return fallback if len(directories) > 1 else directories[0]
def test_ccode_inline_function():
    x = symbols('x')
    g = implemented_function('g', Lambda(x, 2*x))
    assert ccode(g(x)) == "2*x"
    g = implemented_function('g', Lambda(x, 2*x/Catalan))
    assert ccode(
        g(x)) == "double const Catalan = %s;\n2*x/Catalan" % Catalan.n()
    A = IndexedBase('A')
    i = Idx('i', symbols('n', integer=True))
    g = implemented_function('g', Lambda(x, x*(1 + x)*(2 + x)))
    assert ccode(g(A[i]), assign_to=A[i]) == (
        "for (int i=0; i<n; i++){\n"
        "   A[i] = (A[i] + 1)*(A[i] + 2)*A[i];\n"
        "}"
    )