Convert a str into more useful python type (datetime, float, int, bool), if possible

    Some precision may be lost (e.g. Decimal converted to a float)

    >>> try_convert('false')
    False
    >>> try_convert('123456789.123456')
    123456789.123456
    >>> try_convert('1234')
    1234
    >>> try_convert(1234)
    1234
    >>> try_convert(['1234'])
    ['1234']
    >>> try_convert('12345678901234567890123456789012345678901234567890', precise=True)
    12345678901234567890123456789012345678901234567890L
    >>> try_convert('12345678901234567890123456789012345678901234567890.1', precise=True)
    Decimal('12345678901234567890123456789012345678901234567890.1')

def try_convert(value, datetime_to_ms=False, precise=False):
    """Convert a str into more useful python type (datetime, float, int, bool), if possible

    Some precision may be lost (e.g. Decimal converted to a float)

    >>> try_convert('false')
    False
    >>> try_convert('123456789.123456')
    123456789.123456
    >>> try_convert('1234')
    1234
    >>> try_convert(1234)
    1234
    >>> try_convert(['1234'])
    ['1234']
    >>> try_convert('12345678901234567890123456789012345678901234567890', precise=True)
    12345678901234567890123456789012345678901234567890L
    >>> try_convert('12345678901234567890123456789012345678901234567890.1', precise=True)
    Decimal('12345678901234567890123456789012345678901234567890.1')
    """
    if not isinstance(value, basestring):
        return value
    if value in db.YES_VALUES or value in db.TRUE_VALUES:
        return True
    elif value in db.NO_VALUES or value in db.FALSE_VALUES:
        return False
    elif value in db.NULL_VALUES:
        return None
    try:
        if not precise:
            try:
                return int(value)
            except:
                try:
                    return float(value)
                except:
                    pass
        else:
            dec, i, f = None, None, None
            try:
                dec = Decimal(value)
            except:
                return try_convert(value, precise=False)
            try:
                i = int(value)
            except:
                try:
                    f = float(value)
                except:
                    pass
            if dec is not None:
                if dec == i:
                    return i
                elif dec == f:
                    return f
                return dec
    except:
        pass
    try:
        dt = dateutil.parse(value)
        if dt and isinstance(dt, datetime.datetime) and (3000 >= dt.year >= 1900):
            if datetime_to_ms:
                return db.datetime_in_milliseconds(dt)
            return dt
    except:
        pass
    return value