How to use the pdb2pqr.ZSI.wstools.XMLSchema.XMLSchemaComponent function in pdb2pqr

content.append(AttributeReference(self))
                        else:
                            content.append(LocalAttributeDeclaration(self))
                    elif component == 'attributeGroup':
                        content.append(AttributeGroupReference(self))
                    elif component == 'anyAttribute':
                        content.append(AttributeWildCard(self))
                    else:
                        raise (SchemaError, 'Unknown component (%s)'\
                            %(contents[indx].getTagName()))
                    content[-1].fromDom(contents[indx])
                    indx += 1
                self.attr_content = tuple(content)


        class Restriction(XMLSchemaComponent,\
                          RestrictionMarker):
            """
               parents:
                   simpleContent
               attributes:
                   id -- ID
                   base -- QName, required

               contents:
                   annotation?, simpleType?, (enumeration | length | 
                   maxExclusive | maxInclusive | maxLength | minExclusive | 
                   minInclusive | minLength | pattern | fractionDigits | 
                   totalDigits | whiteSpace)*, (attribute | attributeGroup)*, 
                   anyAttribute?
            """
            required = ['base']

def getXMLNS(self, prefix=None):
        """deference prefix or by default xmlns, returns namespace. 
        """
        if prefix == XMLSchemaComponent.xml:
            return XMLNS.XML
        parent = self
        ns = self.attributes[XMLSchemaComponent.xmlns].get(prefix or\
                XMLSchemaComponent.xmlns_key)
        while not ns:
            parent = parent._parent()
            ns = parent.attributes[XMLSchemaComponent.xmlns].get(prefix or\
                    XMLSchemaComponent.xmlns_key)
            if not ns and isinstance(parent, WSDLToolsAdapter):
                if prefix is None:
                    return ''
                raise (SchemaError, 'unknown prefix %s' %prefix)
        return ns

def getElementDeclaration(self, attribute=None):
        """If attribute is None, "ref" is assumed, return the corresponding
        representation of the global element declaration (ElementDeclaration),
        To maintain backwards compat, if attribute is provided call base class method.
        """
        if attribute:
            return XMLSchemaComponent.getElementDeclaration(self, attribute)
        return XMLSchemaComponent.getElementDeclaration(self, 'ref')

def __init__(self, parent=None):
        """parent -- parent instance
           instance variables:
               attributes -- dictionary of node's attributes
        """
        self.attributes = None
        self._parent = parent
        if self._parent:
            self._parent = weakref.ref(parent)

        if not self.__class__ == XMLSchemaComponent\
           and not (type(self.__class__.required) == type(XMLSchemaComponent.required)\
           and type(self.__class__.attributes) == type(XMLSchemaComponent.attributes)\
           and type(self.__class__.contents) == type(XMLSchemaComponent.contents)):
            raise (RuntimeError, 'Bad type for a class variable in %s' %self.__class__)

contents = {'xsd':['annotation', 'restriction', 'extension']}
        tag = 'complexContent'

        def isMixed(self):
            m = self.getAttribute('mixed')
            if m == 0 or m == False:
                return False
            if isinstance(m, basestring) is True:
                if m in ('false', '0'):
                    return False
                if m in ('true', '1'):
                    return True
            raise (SchemaError, 'invalid value for attribute mixed(%s): %s'\
                %(m, self.getItemTrace()))

        class _DerivationBase(XMLSchemaComponent):
            """,
               parents:
                   complexContent
               attributes:
                   id -- ID
                   base -- QName, required

               contents:
                   annotation?, (group | all | choice | sequence)?, 
                       (attribute | attributeGroup)*, anyAttribute?
            """
            required = ['base']
            attributes = {'id':None, 
                'base':None }
            contents = {'xsd':['annotation', 'group', 'all', 'choice',\
                'sequence', 'attribute', 'attributeGroup', 'anyAttribute']}

elif component == 'notation':
                tp = Notation(self)
                tp.fromDom(childNode)
                self.notations[tp.getAttribute('name')] = tp
            elif component == 'complexType':
                tp = ComplexType(self)
                tp.fromDom(childNode)
                self.types[tp.getAttribute('name')] = tp
            elif component == 'simpleType':
                tp = SimpleType(self)
                tp.fromDom(childNode)
                self.types[tp.getAttribute('name')] = tp
            else:
                break

    class Import(XMLSchemaComponent):
        """ 
           parent:
               schema
           attributes:
               id -- ID
               namespace -- anyURI
               schemaLocation -- anyURI
           contents:
               annotation?
        """
        attributes = {'id':None,
                      'namespace':None,
                      'schemaLocation':None}
        contents = {'xsd':['annotation']}
        tag = 'import'

def getAttributeGroup(self, attribute='ref'):
        """attribute -- attribute with a QName value (eg. type).
           collection -- check types collection in parent Schema instance
        """
        return XMLSchemaComponent.getAttributeGroup(self, attribute)

self.annotation = None

    def fromDom(self, node):
        self.setAttributes(node)
        contents = self.getContents(node)

        for i in contents:
            component = SplitQName(i.getTagName())[1]
            if component == 'annotation' and not self.annotation:
                self.annotation = Annotation(self)
                self.annotation.fromDom(i)
            else:
                raise (SchemaError, 'Unknown component (%s)' %(i.getTagName()))


class AttributeReference(XMLSchemaComponent,\
                         AttributeMarker,\
                         ReferenceMarker):
    """
       parents: 
           complexType, restriction, extension, attributeGroup
       attributes:
           id -- ID
           ref -- QName, required
           use -- ('optional' | 'prohibited' | 'required'), optional
           default -- string
           fixed -- string
       contents:
           annotation?
    """
    required = ['ref']
    attributes = {'id':None,

attributes:
           id -- ID
           name -- NCName,  required
           refer -- QName,  required
       contents:
           annotation?, selector, field+
    """
    required = ['name', 'refer']
    attributes = {'id':None, 
        'name':None,
        'refer':None}
    contents = {'xsd':['annotation', 'selector', 'field']}
    tag = 'keyref'


class ElementDeclaration(XMLSchemaComponent,\
                         ElementMarker,\
                         DeclarationMarker):
    """<element name="">
       parents:
           schema
       attributes:
           id -- ID
           name -- NCName,  required
           type -- QName
           default -- string
           fixed -- string
           nillable -- boolean,  false
           abstract -- boolean,  false
           substitutionGroup -- QName
           block -- ('#all' | ('substition' | 'extension' | 'restriction')*), 
               schema.blockDefault </element>

self.setAttributes(node)
        contents = self.getContents(node)

        for i in contents:
            component = SplitQName(i.getTagName())[1]
            if component == 'annotation' and not self.annotation:
                self.annotation = Annotation(self)
                self.annotation.fromDom(i)
            elif component == 'simpleType':
                self.content = AnonymousSimpleType(self)
                self.content.fromDom(i)
            else:
                raise (SchemaError, 'Unknown component (%s)' %(i.getTagName()))


class AttributeWildCard(XMLSchemaComponent,\
                        AttributeMarker,\
                        DeclarationMarker,\
                        WildCardMarker):
    """
       parents: 
           complexType, restriction, extension, attributeGroup
       attributes:
           id -- ID
           namespace -- '##any' | '##other' | 
                        (anyURI* | '##targetNamespace' | '##local'), ##any
           processContents -- 'lax' | 'skip' | 'strict', strict
       contents:
           annotation?
    """
    attributes = {'id':None, 
        'namespace':'##any',