s = """<!DOCTYPE root [
...   <!ELEMENT root ANY>
...   <!ELEMENT Person ANY>
...   <!ELEMENT Customer EMPTY>
...   <!ELEMENT Team EMPTY>
...   <!ATTLIST Person SSN ID #REQUIRED>
...   <!ATTLIST Customer id IDREF #REQUIRED>
...   <!ATTLIST Team members IDREFS #REQUIRED>
...   <!ATTLIST Person test CDATA "4">
... ]>
... <root>
...   <Person SSN='A111'/>
...   <Person SSN='A112'/>
...   <Person SSN='A222'/>
...   <Customer id='A111'/>
...   <Customer id='A222334444'/>
...   <Team members='A222334444 A333445555'/>
... </root>"""
>>> e = etree.parse(StringIO(s), etree.XMLParser(load_dtd=True, attribute_defaults=True))
>>> e.docinfo.internalDTD.elements()[1]
<lxml.etree._DTDElementDecl object name='Person' prefix=None type='any' at 0x7f518f7462d0>
>>> e.docinfo.internalDTD.elements()[1].attributes()
[]
>>> for i in e.getroot():
...   if i.tag == "Person":
...     print(i.attrib)
...
{'SSN': 'A111', 'test': '4'}
{'SSN': 'A112', 'test': '4'}
{'SSN': 'A222', 'test': '4'}
>>> d = etree.DTD(StringIO("""  <!ELEMENT root ANY>
...   <!ELEMENT Person ANY>
...   <!ELEMENT Customer EMPTY>
...   <!ELEMENT Team EMPTY>
...   <!ATTLIST Person SSN ID #REQUIRED>
...   <!ATTLIST Customer id IDREF #REQUIRED>
...   <!ATTLIST Team members IDREFS #REQUIRED>
...   <!ATTLIST Person test CDATA "4">
... """))
>>> d.elements()[1]
<lxml.etree._DTDElementDecl object name='Person' prefix=None type='any' at 0x7f518f7463d0>
>>> d.elements()[1].attributes()
[<lxml.etree._DTDAttributeDecl object name='SSN' elemname='Person' prefix=None type='id' default='required' default_value=None at 0x7f518f746310>, <lxml.etree._DTDAttributeDecl object name='test' elemname='Person' prefix=None type='cdata' default='none' default_value='4' at 0x7f518f746350>]
>>>