Mathml tweaks indent

mathics/builtin/forms/print.py

@@ -161,7 +161,6 @@ class OutputForm(FormBaseClass):
     in_outputforms = True
     in_printforms = True
 
-    formats = {"OutputForm[s_String]": "s"}
     summary_text = "format expression in plain text"
 
 

mathics/doc/doc_entries.py

@@ -10,7 +10,6 @@
 import logging
 import re
 from abc import ABC
-from os import getenv
 from typing import TYPE_CHECKING, Callable, Dict, List, Optional, Sequence, Tuple
 
 from mathics.core.evaluation import Message, Print, _Out

mathics/format/box/outputforms.py

@@ -30,7 +30,7 @@ def eval_mathmlform(expr: BaseElement, evaluation: Evaluation) -> BoxElementMixi
 
     boxes = format_element(expr, evaluation, SymbolTraditionalForm)
     try:
-        mathml = boxes.boxes_to_mathml(evaluation=evaluation)
+        mathml = boxes.boxes_to_mathml(evaluation=evaluation, _indent_level=1)
     except BoxError:
         evaluation.message(
             "General",
@@ -44,9 +44,15 @@ def eval_mathmlform(expr: BaseElement, evaluation: Evaluation) -> BoxElementMixi
     # #convert_box(boxes)
     query = evaluation.parse("Settings`$UseSansSerif")
     usesansserif = query.evaluate(evaluation).to_python()
-    if not is_a_picture:
-        if isinstance(usesansserif, bool) and usesansserif:
-            mathml = '<mstyle mathvariant="sans-serif">%s</mstyle>' % mathml
+    if is_a_picture:
+        usesansserif = False
+    elif not isinstance(usesansserif, bool):
+        usesansserif = False
+
+    if usesansserif:
+        mathml = '<mstyle mathvariant="sans-serif">\n%s\n</mstyle>' % mathml
+    else:
+        mathml = "\n%s\n" % mathml
 
     mathml = '<math display="block">%s</math>' % mathml  # convert_box(boxes)
     return InterpretationBox(