Troubleshoot & Fix: TypeError - Unexpected 'transport_encoding' Keyword Argument in Parse() Function

In this guide, we will address the TypeError that occurs when an unexpected transport_encoding keyword argument is passed to the parse() function. This issue commonly arises when working with various parsing libraries in Python, such as BeautifulSoup and lxml. By following the step-by-step solution provided in this guide, you can quickly resolve this error and get back to developing your application.

Table of Contents

Understanding the Issue

Before diving into the solution, it's crucial to understand the cause of the error. The TypeError occurs when the transport_encoding keyword argument is unexpectedly passed to the parse() function in a parsing library.

In most cases, the transport_encoding argument is not required, and the error arises due to a misconfiguration or incorrect usage of the library.

Some common scenarios where this error might occur include:

  • Using an outdated version of the library
  • Incorrectly passing the transport_encoding argument to the parse() function
  • Incompatibility issues between different libraries

Step-by-step Solution

Follow these steps to resolve the TypeError regarding the unexpected transport_encoding keyword argument in the parse() function:

  1. Check the library version: Ensure that you are using the latest version of the parsing library. Outdated versions might not support the transport_encoding argument or might have bugs that cause this error. Update the library if needed.
# For BeautifulSoup
pip install --upgrade beautifulsoup4

# For lxml
pip install --upgrade lxml
  1. Verify the usage of the parse() function: Make sure that you are using the parse() function correctly. The transport_encoding argument should not be passed directly to the parse() function. Instead, you should pass the encoding to the open() function when reading the file.
# Incorrect usage
from lxml import etree
tree = etree.parse("example.xml", transport_encoding="utf-8")

# Correct usage
from lxml import etree
with open("example.xml", encoding="utf-8") as file:
    tree = etree.parse(file)

Check for library incompatibilities: If you are using multiple libraries that interact with the parse() function, ensure that they are compatible with each other. For instance, if you are using both BeautifulSoup and lxml, make sure that both libraries are up-to-date and that their versions are compatible.

Consider an alternative parsing library: If the above steps do not resolve the issue, consider using another parsing library that does not have compatibility issues or known bugs related to the transport_encoding argument.


Q: Can I use the transport_encoding argument with BeautifulSoup's parse() function?

A: BeautifulSoup does not have a parse() function. Instead, it uses the BeautifulSoup() constructor to parse HTML and XML documents. You can pass the transport_encoding argument to the open() function when reading the file before passing the file object to BeautifulSoup().

from bs4 import BeautifulSoup
with open("example.html", encoding="utf-8") as file:
    soup = BeautifulSoup(file, "html.parser")

Q: Are there any alternatives to lxml and BeautifulSoup for parsing HTML and XML in Python?

A: Yes, there are several alternatives, including the built-in ElementTree library for XML parsing and html5lib for HTML parsing.

Q: How can I determine the appropriate encoding for my file?

A: You can use the chardet library to automatically detect the encoding of a file.

import chardet
with open("example.html", "rb") as file:
    encoding = chardet.detect(["encoding"]

Q: How important is it to specify the encoding when parsing a file?

A: Specifying the encoding when parsing a file is crucial when dealing with non-ASCII characters. If the encoding is not specified, the parser might not correctly interpret the characters, leading to unexpected behavior or errors.

Q: Can I use the transport_encoding argument with Python's built-in open() function?

A: The transport_encoding argument is not used with the built-in open() function in Python. Instead, the encoding argument is used to specify the character encoding.

with open("example.html", encoding="utf-8") as file:
    content =

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