Validate the class entries.

def _validate(self):
        """Validate the class entries.
        """
        checker = (self._check0, self._check1, self._check2, self._check3,
                   self._check4, self._check5)
        if not 0 <= self.field_type <= 5:
            raise NotImplementedError("unsupported widget type")
        if type(self.rect) is not Rect:
            raise ValueError("invalid rect")
        if self.rect.isInfinite or self.rect.isEmpty:
            raise ValueError("rect must be finite and not empty")
        if not self.field_name:
            raise ValueError("field name missing")

        if self.border_color:
            if not len(self.border_color) in range(1,5) or \
               type(self.border_color) not in (list, tuple):
               raise ValueError("border_color must be 1 - 4 floats")

        if self.fill_color:
            if not len(self.fill_color) in range(1,5) or \
               type(self.fill_color) not in (list, tuple):
               raise ValueError("fill_color must be 1 - 4 floats")

        if not self.text_color:
            self.text_color = (0, 0, 0)
        if not len(self.text_color) in range(1,5) or \
            type(self.text_color) not in (list, tuple):
            raise ValueError("text_color must be 1 - 4 floats")

        if not self.border_width:
            self.border_width = 0

        if not self.text_fontsize:
            self.text_fontsize = 0

        checker[self.field_type]()