Apply conversions mentioned above.

def convert_field(self, value, conversion):
        """Apply conversions mentioned above."""
        func = self.CONV_FUNCS.get(conversion)
        if func is not None:
            value = getattr(value, func)()
        elif conversion not in ['R']:
            # default conversion ('r', 's')
            return super(StringFormatter, self).convert_field(value, conversion)

        if conversion in ['h', 'H', 'R']:
            value = value.replace('-', '').replace('_', '').replace(':', '').replace(' ', '')
        return value