def convert(date, time=None, tzinfo=None, locale='iso'):
    """Convert the input to a datetime object.

    The convert function accepts unicode or non-unicode strings and tries
    to parse out Date and Time information as follows:
      * First try to get the localized datetime pattern information
      * If no one is found, a default pattern is used.
      * Parse the input by the definitions of the localized datetime pattern
      * Create a datetime object and return it

    The 'intelligence' is defined by following behaviour:

    Date:
      * If only one value is found f.e. '1', this value is handled as the
        day value, for month and for year the current ones are used.
      * Respective, if two values are given, they are handled as day and
        month, year is auto completed with the current year.
      * 3 values are a complete date information, if year is a 2-character
        string, it is handled as year in the current century
      * as limiters are all non-numeric values accepted
      * date input can be done without limiters, therefor all characters
        must be numbers, and the string length must be either 2, 4, 6 or 8
        characters. 2 characters define the day, 4 characters the day and
        the month, 6 characters day, month and the year of the current
        century and 8 characters define a complete date.

    Time:
      * If time is None, time is set to 00:00
      * if time is a 2-character string, it is handled as the hour, minutes
        are defined as 00
      * time input can be done without a limiter, therefor time must be an
        all numeric 4-character string, the first 2 chars are handled as
        hour, the second 2 chars as minute.
      * as limiter are all non-numeric values accepted
      * seconds are never computed and are therefor ALWAYS handled as '00'

    Limiters can be any 1 or more character non numeric values. An input
    can look like ``  %_2008 1 abcde 5 ---`` and is still valid and with
    default locale converted to ``datetime.datetime(2008, 1, 5, 0, 0)``.

    If parsing of the input values is not possible or converting the parsed
    values to numeric values is not possible or the valid date and time
    range falls out of scope, a ``DateTimeConversionError`` is raised.

    @param date - a date as string
    @param time - a time as string
    @param tzinfo - a tzinfo object to be considered, defaults to None. If
                    given the date and time taken as in the given timezone.
                    If the timezone is DST-aware time will be normalized
                    for DST/non-DST.
    @param locale - a locale name, which is used to determine the date and
                    time patterns. There exists a special locale named
                    'iso', which is default and expects the input in ISO
                    format.
    @return datetime - datetime.datetime object
    @raise DateTimeConversionError - if conversion fails
    """