def __init__(self,name, value, rfc2425parameters = None, empty_ok = False):
_unused = rfc2425parameters<EOL>VCardField.__init__(self,name)<EOL>if isinstance(value,libxml2.xmlNode):<EOL><INDENT>value=value.getContent()<EOL>if value:<EOL><INDENT>self.value=unicode(value,"<STR_LIT:utf-8>","<STR_LIT:replace>").strip()<EOL><DEDENT>else:<EOL><INDENT>self.value=u"<STR_LIT>"<EOL><DEDENT><DEDENT>else:<EOL><INDENT>self.value=value<EOL><DEDENT>if not self.value and not empty_ok:<EOL><INDENT>raise Empty("<STR_LIT>")<EOL><DEDENT>
Initialize a `VCardString` object.

        :Parameters:
            - `name`: field name
            - `value`: field value as string or an XML node
            - `rfc2425parameters`: optional RFC 2425 parameters
        :Types:
            - `name`: `str`
            - `value`: `str` or `libxml2.xmlNode`
            - `rfc2425parameters`: `dict`