diff --git a/lib/Docopt.php b/lib/Docopt.php
index d6a1939..349904d 100644
--- a/lib/Docopt.php
+++ b/lib/Docopt.php
@@ -38,32 +38,33 @@ class Docopt {
      * --options, <positional-argument>, commands, which could be
      * [optional], (required), (mutually | exclusive) or repeated...
      * 
-     * Example
-     * -------
+     * Example:
      * 
-     * > use MensBeam\Docopt\Docopt;
-     * > $doc = <<<DOCSTRING
-     * <<< Usage:
-     * <<<     my_program tcp <host> <port> [--timeout=<seconds>]
-     * <<<     my_program serial <port> [--baud=<n>] [--timeout=<seconds>]
-     * <<<     my_program (-h | --help | --version)
-     * <<<
-     * <<< Options:
-     * <<<     -h, --help  Show this screen and exit.
-     * <<<     --baud=<n>  Baudrate [default: 9600]
-     * <<< DOCSTRING;
-     * > $argv = ['tcp', '127.0.0.1', '80', '--timeout', '30'];
-     * > echo json_encode(Docopt::docopt($doc, $argv), \JSON_PRETTY_PRINT);
-     * {
-     *     "--baud": "9600",
-     *     "--help": false,
-     *     "--timeout": "30",
-     *     "--version": false,
-     *     "<host>": "127.0.0.1",
-     *     "<port>": "80",
-     *     "serial": false,
-     *     "tcp": true
-     * }
+     * ```
+     * use MensBeam\Docopt\Docopt;
+     * $doc = <<<DOCSTRING
+     * Usage:
+     *     my_program tcp <host> <port> [--timeout=<seconds>]
+     *     my_program serial <port> [--baud=<n>] [--timeout=<seconds>]
+     *     my_program (-h | --help | --version)
+     * 
+     * Options:
+     *     -h, --help  Show this screen and exit.
+     *     --baud=<n>  Baudrate [default: 9600]
+     * DOCSTRING;
+     * $argv = ['tcp', '127.0.0.1', '80', '--timeout', '30'];
+     * echo json_encode(Docopt::docopt($doc, $argv), \JSON_PRETTY_PRINT);
+     * //{
+     * //    "--baud": "9600",
+     * //    "--help": false,
+     * //    "--timeout": "30",
+     * //    "--version": false,
+     * //    "<host>": "127.0.0.1",
+     * //    "<port>": "80",
+     * //    "serial": false,
+     * //    "tcp": true
+     * //}
+     * ```
      *
      * @param string $docstring Description of your command-line interface
      * @param string[]|string|null $argv Argument list to be parsed. $_SERVER['argv'] is used if null is provided
@@ -81,6 +82,7 @@ class Docopt {
         bool $more_magic = false
     ): ParsedOptions {
         # argv = sys.argv[1:] if argv is None else argv
+        $argv = $argv ?? array_slice($_SERVER['argv'] ?? [], 1);
         # maybe_frame = inspect.currentframe()
         # if maybe_frame:
         #     parent_frame = doc_parent_frame = magic_parent_frame = maybe_frame.f_back
@@ -91,6 +93,8 @@ class Docopt {
         #             more_magic = True
         #         else:
         #             magic_parent_frame = magic_parent_frame.f_back
+        // DEVIATION: All these lines are to do with automatic invocation of the "magic" variant of docopt()
+        //   We cannot do this in PHP
         # if not docstring:  # go look for one, if none exists, raise Exception
         #     while not docstring and doc_parent_frame:
         #         docstring = doc_parent_frame.f_locals.get("__doc__")
@@ -98,6 +102,7 @@ class Docopt {
         #             doc_parent_frame = doc_parent_frame.f_back
         #     if not docstring:
         #         raise DocoptLanguageError("Either __doc__ must be defined in the scope of a parent or passed as the first argument.")
+        // DEVIATION: All these lines look for a docstring in the parent context. We simply require one as input
         # output_value_assigned = False
         # if more_magic and parent_frame:
         #     import dis
@@ -110,14 +115,27 @@ class Docopt {
         #     MAYBE_STORE = next(instrs)
         #     if MAYBE_STORE and (MAYBE_STORE.opname.startswith("STORE") or MAYBE_STORE.opname.startswith("RETURN")):
         #         output_value_assigned = True
+        // DEVIATION: This is all for magic which is not possible in PHP
+
         # usage_sections = parse_section("usage:", docstring)
         # if len(usage_sections) == 0:
         #     raise DocoptLanguageError('"usage:" section (case-insensitive) not found. Perhaps missing indentation?')
         # if len(usage_sections) > 1:
         #     raise DocoptLanguageError('More than one "usage:" (case-insensitive).')
+        $usage_sections = Util::parse_section("usage:", $docstring);
+        if (sizeof($usage_sections) === 0) {
+            throw new DocoptLanguageError('"usage:" section (case-insensitive) not found. Perhaps missing indentation?');
+        }
+        if (sizeof($usage_sections) > 1) {
+            throw new DocoptLanguageError('More than one "usage:" (case-insensitive).');
+        }
         # options_pattern = re.compile(r"\n\s*?options:", re.IGNORECASE)
         # if options_pattern.search(usage_sections[0]):
         #     raise DocoptExit("Warning: options (case-insensitive) was found in usage." "Use a blank line between each section..")
+        $options_pattern = '/\n\s*?options:/si';
+        if (preg_match($options_pattern, $usage_sections[0])) {
+            throw new DocoptExit("Warning: options (case-insensitive) was found in usage."."Use a blank line between each section..");
+        }
         # DocoptExit.usage = usage_sections[0]
         # options = parse_defaults(docstring)
         # pattern = parse_pattern(formal_usage(DocoptExit.usage), options)