# Buggy code
def array2string(
    a,
    max_line_width=None,
    precision=None,
    suppress_small=None,
    separator=" ",
    prefix="",
    style=np._NoValue,
    formatter=None,
    threshold=None,
    edgeitems=None,
    sign=None,
    floatmode=None,
    suffix="",
    **kwarg,
):
    """
    Return a string representation of an array.

    Parameters
    ----------
    a : array_like
        Input array.
    max_line_width : int, optional
        The maximum number of columns the string should span. Newline
        characters splits the string appropriately after array elements.
    precision : int or None, optional
        Floating point precision. Default is the current printing
        precision (usually 8), which can be altered using `set_printoptions`.
    suppress_small : bool, optional
        Represent very small numbers as zero. A number is "very small" if it
        is smaller than the current printing precision.
    separator : str, optional
        Inserted between elements.
    prefix : str, optional
    suffix: str, optional
        The length of the prefix and suffix strings are used to respectively
        align and wrap the output. An array is typically printed as::

          prefix + array2string(a) + suffix

        The output is left-padded by the length of the prefix string, and
        wrapping is forced at the column ``max_line_width - len(suffix)``.
    style : _NoValue, optional
        Has no effect, do not use.

        .. deprecated:: 1.14.0
    formatter : dict of callables, optional
        If not None, the keys should indicate the type(s) that the respective
        formatting function applies to.  Callables should return a string.
        Types that are not specified (by their corresponding keys) are handled
        by the default formatters.  Individual types for which a formatter
        can be set are::

            - 'bool'
            - 'int'
            - 'timedelta' : a `numpy.timedelta64`
            - 'datetime' : a `numpy.datetime64`
            - 'float'
            - 'longfloat' : 128-bit floats
            - 'complexfloat'
            - 'longcomplexfloat' : composed of two 128-bit floats
            - 'void' : type `numpy.void`
            - 'numpystr' : types `numpy.string_` and `numpy.unicode_`
            - 'str' : all other strings

        Other keys that can be used to set a group of types at once are::

            - 'all' : sets all types
            - 'int_kind' : sets 'int'
            - 'float_kind' : sets 'float' and 'longfloat'
            - 'complex_kind' : sets 'complexfloat' and 'longcomplexfloat'
            - 'str_kind' : sets 'str' and 'numpystr'
    threshold : int, optional
        Total number of array elements which trigger summarization
        rather than full repr.
    edgeitems : int, optional
        Number of array items in summary at beginning and end of
        each dimension.
    sign : string, either '-', '+', or ' ', optional
        Controls printing of the sign of floating-point types. If '+', always
        print the sign of positive values. If ' ', always prints a space
        (whitespace character) in the sign position of positive values.  If
        '-', omit the sign character of positive values.
    floatmode : str, optional
        Controls the interpretation of the `precision` option for
        floating-point types. Can take the following values:
            - 'fixed' : Always print exactly `precision` fractional digits,
                    even if this would print more or fewer digits than
                    necessary to specify the value uniquely.
            - 'unique : Print the minimum number of fractional digits necessary
                    to represent each value uniquely. Different elements may
                    have a different number of digits.  The value of the
                    `precision` option is ignored.
            - 'maxprec' : Print at most `precision` fractional digits, but if
                    an element can be uniquely represented with fewer digits
                    only print it with that many.
            - 'maxprec_equal' : Print at most `precision` fractional digits,
                    but if every element in the array can be uniquely
                    represented with an equal number of fewer digits, use that
                    many digits for all elements.
    legacy : string or `False`, optional
        If set to the string `'1.13'` enables 1.13 legacy printing mode. This
        approximates numpy 1.13 print output by including a space in the sign
        position of floats and different behavior for 0d arrays. If set to
        `False`, disables legacy mode. Unrecognized strings will be ignored
        with a warning for forward compatibility.

        .. versionadded:: 1.14.0

    Returns
    -------
    array_str : str
        String representation of the array.

    Raises
    ------
    TypeError
        if a callable in `formatter` does not return a string.

    See Also
    --------
    array_str, array_repr, set_printoptions, get_printoptions

    Notes
    -----
    If a formatter is specified for a certain type, the `precision` keyword is
    ignored for that type.

    This is a very flexible function; `array_repr` and `array_str` are using
    `array2string` internally so keywords with the same name should work
    identically in all three functions.

    Examples
    --------
    >>> x = np.array([1e-16,1,2,3])
    >>> print(np.array2string(x, precision=2, separator=',',
    ...                       suppress_small=True))
    [ 0., 1., 2., 3.]

    >>> x  = np.arange(3.)
    >>> np.array2string(x, formatter={'float_kind':lambda x: "%.2f" % x})
    '[0.00 1.00 2.00]'

    >>> x  = np.arange(3)
    >>> np.array2string(x, formatter={'int':lambda x: hex(x)})
    '[0x0L 0x1L 0x2L]'

    """
    legacy = kwarg.pop("legacy", None)
    if kwarg:
        msg = "array2string() got unexpected keyword argument '{}'"
        raise TypeError(msg.format(kwarg.popitem()[0]))

    overrides = _make_options_dict(
        precision,
        threshold,
        edgeitems,
        max_line_width,
        suppress_small,
        None,
        None,
        sign,
        formatter,
        floatmode,
        legacy,
    )
    options = _format_options.copy()
    options.update(overrides)

    if options["legacy"] == "1.13":
        if a.shape == () and not a.dtype.names:
            return style(a.item())
    elif style is not np._NoValue:
        # Deprecation 11-9-2017  v1.14
        warnings.warn(
            "'style' argument is deprecated and no longer functional"
            " except in 1.13 'legacy' mode",
            DeprecationWarning,
            stacklevel=3,
        )

    if options["legacy"] != "1.13":
        options["linewidth"] -= len(suffix)

    # treat as a null array if any of shape elements == 0
    if a.size == 0:
        return "[]"

    return _array2string(a, options, separator, prefix)


# Traceback (TypeError)
import numpy as np
np.__version__
'1.14.2'
np.array2string(np.array(1.0))
'1.'
np.set_printoptions(legacy='1.13')
np.array2string(np.array(1.0))
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "[...]/numpy/core/arrayprint.py", line 616, in array2string
return style(a.item())
TypeError: object() takes no parameters

# Fixed code
def array2string(
    a,
    max_line_width=None,
    precision=None,
    suppress_small=None,
    separator=" ",
    prefix="",
    style=np._NoValue,
    formatter=None,
    threshold=None,
    edgeitems=None,
    sign=None,
    floatmode=None,
    suffix="",
    **kwarg,
):
    """
    Return a string representation of an array.

    Parameters
    ----------
    a : array_like
        Input array.
    max_line_width : int, optional
        The maximum number of columns the string should span. Newline
        characters splits the string appropriately after array elements.
    precision : int or None, optional
        Floating point precision. Default is the current printing
        precision (usually 8), which can be altered using `set_printoptions`.
    suppress_small : bool, optional
        Represent very small numbers as zero. A number is "very small" if it
        is smaller than the current printing precision.
    separator : str, optional
        Inserted between elements.
    prefix : str, optional
    suffix: str, optional
        The length of the prefix and suffix strings are used to respectively
        align and wrap the output. An array is typically printed as::

          prefix + array2string(a) + suffix

        The output is left-padded by the length of the prefix string, and
        wrapping is forced at the column ``max_line_width - len(suffix)``.
    style : _NoValue, optional
        Has no effect, do not use.

        .. deprecated:: 1.14.0
    formatter : dict of callables, optional
        If not None, the keys should indicate the type(s) that the respective
        formatting function applies to.  Callables should return a string.
        Types that are not specified (by their corresponding keys) are handled
        by the default formatters.  Individual types for which a formatter
        can be set are::

            - 'bool'
            - 'int'
            - 'timedelta' : a `numpy.timedelta64`
            - 'datetime' : a `numpy.datetime64`
            - 'float'
            - 'longfloat' : 128-bit floats
            - 'complexfloat'
            - 'longcomplexfloat' : composed of two 128-bit floats
            - 'void' : type `numpy.void`
            - 'numpystr' : types `numpy.string_` and `numpy.unicode_`
            - 'str' : all other strings

        Other keys that can be used to set a group of types at once are::

            - 'all' : sets all types
            - 'int_kind' : sets 'int'
            - 'float_kind' : sets 'float' and 'longfloat'
            - 'complex_kind' : sets 'complexfloat' and 'longcomplexfloat'
            - 'str_kind' : sets 'str' and 'numpystr'
    threshold : int, optional
        Total number of array elements which trigger summarization
        rather than full repr.
    edgeitems : int, optional
        Number of array items in summary at beginning and end of
        each dimension.
    sign : string, either '-', '+', or ' ', optional
        Controls printing of the sign of floating-point types. If '+', always
        print the sign of positive values. If ' ', always prints a space
        (whitespace character) in the sign position of positive values.  If
        '-', omit the sign character of positive values.
    floatmode : str, optional
        Controls the interpretation of the `precision` option for
        floating-point types. Can take the following values:
            - 'fixed' : Always print exactly `precision` fractional digits,
                    even if this would print more or fewer digits than
                    necessary to specify the value uniquely.
            - 'unique : Print the minimum number of fractional digits necessary
                    to represent each value uniquely. Different elements may
                    have a different number of digits.  The value of the
                    `precision` option is ignored.
            - 'maxprec' : Print at most `precision` fractional digits, but if
                    an element can be uniquely represented with fewer digits
                    only print it with that many.
            - 'maxprec_equal' : Print at most `precision` fractional digits,
                    but if every element in the array can be uniquely
                    represented with an equal number of fewer digits, use that
                    many digits for all elements.
    legacy : string or `False`, optional
        If set to the string `'1.13'` enables 1.13 legacy printing mode. This
        approximates numpy 1.13 print output by including a space in the sign
        position of floats and different behavior for 0d arrays. If set to
        `False`, disables legacy mode. Unrecognized strings will be ignored
        with a warning for forward compatibility.

        .. versionadded:: 1.14.0

    Returns
    -------
    array_str : str
        String representation of the array.

    Raises
    ------
    TypeError
        if a callable in `formatter` does not return a string.

    See Also
    --------
    array_str, array_repr, set_printoptions, get_printoptions

    Notes
    -----
    If a formatter is specified for a certain type, the `precision` keyword is
    ignored for that type.

    This is a very flexible function; `array_repr` and `array_str` are using
    `array2string` internally so keywords with the same name should work
    identically in all three functions.

    Examples
    --------
    >>> x = np.array([1e-16,1,2,3])
    >>> print(np.array2string(x, precision=2, separator=',',
    ...                       suppress_small=True))
    [ 0., 1., 2., 3.]

    >>> x  = np.arange(3.)
    >>> np.array2string(x, formatter={'float_kind':lambda x: "%.2f" % x})
    '[0.00 1.00 2.00]'

    >>> x  = np.arange(3)
    >>> np.array2string(x, formatter={'int':lambda x: hex(x)})
    '[0x0L 0x1L 0x2L]'

    """
    legacy = kwarg.pop("legacy", None)
    if kwarg:
        msg = "array2string() got unexpected keyword argument '{}'"
        raise TypeError(msg.format(kwarg.popitem()[0]))

    overrides = _make_options_dict(
        precision,
        threshold,
        edgeitems,
        max_line_width,
        suppress_small,
        None,
        None,
        sign,
        formatter,
        floatmode,
        legacy,
    )
    options = _format_options.copy()
    options.update(overrides)

    if options["legacy"] == "1.13":
        if style is np._NoValue:
            style = repr

        if a.shape == () and not a.dtype.names:
            return style(a.item())
    elif style is not np._NoValue:
        # Deprecation 11-9-2017  v1.14
        warnings.warn(
            "'style' argument is deprecated and no longer functional"
            " except in 1.13 'legacy' mode",
            DeprecationWarning,
            stacklevel=3,
        )

    if options["legacy"] != "1.13":
        options["linewidth"] -= len(suffix)

    # treat as a null array if any of shape elements == 0
    if a.size == 0:
        return "[]"

    return _array2string(a, options, separator, prefix)