<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def cssify(css_dict):
 """Function to get CartoCSS from Python dicts"""

    css = ''
    for key, value in dict_items(css_dict):
        css += '{key} {{ '.format(key=key)
        for field, field_value in dict_items(value):
            css += ' {field}: {field_value};'.format(field=field,
                                                     field_value=field_value)
        css += '} '
    return css.strip()