case r == '_', r == '$':
			return r
		default:
			valid = false
			return -1
		}
	}, name)

	if valid {
		// check for simple name or quoted name
		// - letter/underscore followed by one or more letter/digit/underscore
		// - any text between quotes (text cannot contain a quote itself)
		if match, err := regexp.MatchString("^[a_][a0_$]*$", cleaned); err != nil {
			return err
		} else if match {
			return nil

But a variable like `user-agent` is invalid in Python.

So, by default, `Header` will convert the parameter names characters from underscore (`_`) to hyphen (`-`) to extract and document the headers.

Also, HTTP headers are case-insensitive, so, you can declare them with standard Python style (also known as "snake_case").

 *
 * <p>If not all classes on the classpath should be covered, {@link #ignoreClasses} can be used to
 * exclude certain classes. As a special case, classes with an underscore in the name (like {@code
 * AutoValue_Foo}) can be excluded using <code>ignoreClasses({@link #UNDERSCORE_IN_NAME})</code>.
 *
 * <p>{@link #setDefault} allows subclasses to specify default values for types.
 *

 *
 * <p>If not all classes on the classpath should be covered, {@link #ignoreClasses} can be used to
 * exclude certain classes. As a special case, classes with an underscore in the name (like {@code
 * AutoValue_Foo}) can be excluded using <code>ignoreClasses({@link #UNDERSCORE_IN_NAME})</code>.
 *
 * <p>{@link #setDefault} allows subclasses to specify default values for types.
 *

     * <p>ASCII characters in the part are expected to be valid per RFC 1035, with underscore also
     * being allowed due to widespread practice.
     */

    String asciiChars = CharMatcher.ascii().retainFrom(part);

    if (!PART_CHAR_MATCHER.matchesAllOf(asciiChars)) {
      return false;
    }

    // No initial or final dashes or underscores.

    if (DASH_MATCHER.matches(part.charAt(0))

disable the `permessage-deflate` compression settings on your server.

Note that OkHttp won't use compression when sending messages smaller than 1 KiB.

 *  Fix: Don't crash when the URL hostname contains an underscore on Android.
 *  Fix: Change HTTP/2 to use a daemon thread for its socket reader. If you've ever seen a command
    line application hang after all of the work is done, it may be due to a non-daemon thread like
    this one.

		// A is 65, a is 97
		if v >= 'a' {
			b.WriteRune(v)
			continue
		}
		// v is capital letter here
		// disregard first letter
		// add underscore if last letter is capital letter
		// add underscore when previous letter is lowercase
		// add underscore when next letter is lowercase
		if (i != 0 || i == l-1) && ((i > 0 && rune(camel[i-1]) >= 'a') ||
			(i < l-1 && rune(camel[i+1]) >= 'a')) {
			b.WriteRune('_')

     * <p>ASCII characters in the part are expected to be valid per RFC 1035, with underscore also
     * being allowed due to widespread practice.
     */

    String asciiChars = CharMatcher.ascii().retainFrom(part);

    if (!PART_CHAR_MATCHER.matchesAllOf(asciiChars)) {
      return false;
    }

    // No initial or final dashes or underscores.

    if (DASH_MATCHER.matches(part.charAt(0))

	return b
}

// isSeparator reports whether the rune could mark a word boundary.
// TODO: update when package unicode captures more of the properties.
func isSeparator(r rune) bool {
	// ASCII alphanumerics and underscore are not separators
	if r <= 0x7F {
		switch {
		case '0' <= r && r <= '9':
			return false
		case 'a' <= r && r <= 'z':
			return false
		case 'A' <= r && r <= 'Z':
			return false
		case r == '_':

and <code>A</code> through <code>F</code> represent values 10 through 15.
</p>

<p>
For readability, an underscore character <code>_</code> may appear after
a base prefix or between successive digits; such underscores do not change
the literal's value.
</p>
<pre class="ebnf">
int_lit        = decimal_lit | binary_lit | octal_lit | hex_lit .