If you found a bug in python-ldap, or would request a new feature,
this is the place to let us know.

Please describe the issue and your environment here.

Issue description:
Example at the following link:
https://github.com/python-ldap/python-ldap/blob/master/Doc/reference/ldif.rst#example

import sys,ldif
entry={'objectClass':['top','person'],'cn':['Michael Stroeder'],'sn':['Stroeder']}
dn='cn=Michael Stroeder,ou=Test'
ldif_writer=ldif.LDIFWriter(sys.stdout)
ldif_writer.unparse(dn,entry)

When entering this code in the python console, the following error is received:
Traceback (most recent call last):
File "", line 1, in
File "/Users/plainid/PycharmProjects/LDIF_Generator/venv/lib/python3.7/site-packages/ldif.py", line 198, in unparse
self._unparseEntryRecord(record)
File "/Users/plainid/PycharmProjects/LDIF_Generator/venv/lib/python3.7/site-packages/ldif.py", line 155, in _unparseEntryRecord
self._unparseAttrTypeandValue(attr_type,attr_value)
File "/Users/plainid/PycharmProjects/LDIF_Generator/venv/lib/python3.7/site-packages/ldif.py", line 139, in _unparseAttrTypeandValue
if self._needs_base64_encoding(attr_type,attr_value):
File "/Users/plainid/PycharmProjects/LDIF_Generator/venv/lib/python3.7/site-packages/ldif.py", line 128, in _needs_base64_encoding
not safe_string_re.search(attr_value) is None
TypeError: cannot use a bytes pattern on a string-like object

Steps to reproduce:
Enter example from documentation in python console

Fix is simple, mark the entry attribute strings as bytestrings:
entry={"objectClass":[b"top",b"person"],"cn":[b"Michael Stroeder"],"sn":[b"Stroeder"]}

Operating system:
Mac OS
Python version:
3.7
python-ldap version:
3.2.0