Conversion Error: 'Item' object has no attribute 'xpath'

-----------------------------------------------------------------------

calibre, version 3.12.0 (win32, embedded-python: True)
Conversion error: Failed: Convert book 1 of 1 (The Lean Muscle Diet: A Customized Nutrition and Workout Plan--Eat the Foods You Love to Build the Body You Want and Keep It for Life!)

Convert book 1 of 1 (The Lean Muscle Diet: A Customized Nutrition and Workout Plan--Eat the Foods You Love to Build the Body You Want and Keep It for Life!)
Conversion options changed from defaults:
read_metadata_from_opf: u'C:\\Users\\Kevin\\AppData\\Local\\Temp\\calibre_ ynk6si\\l4en4t.opf'
margin_right: -1.0
remove_fake_margins: False
max_toc_links: 0
verbose: 2
margin_left: -1.0
margin_top: -1.0
cover: u'C:\\Users\\Kevin\\AppData\\Local\\Temp\\calibre_ ynk6si\\xcm0kg.jpeg'
expand_css: True
no_chapters_in_toc: True
disable_font_rescaling: True
pdf_default_font_size: 16
custom_size: u'6.8 x 9.5'
pdf_sans_family: u'Liberation Mono'
keep_ligatures: True
embed_all_fonts: True
output_profile: 'tablet'
input_profile: 'kindle'
margin_bottom: -1.0
minimum_line_height: 0.0
Resolved conversion options
calibre version: 3.12.0
{'asciiize': False,
'author_sort': None,
'authors': None,
'base_font_size': 0.0,
'book_producer': None,
'change_justification': u'original',
'chapter': u"//*[((name()='h1' or name()='h2') and re:test(., '\\s*((chapter|book|section|part)\\s+)|((prolog|pr ologue|epilogue)(\\s+|$))', 'i')) or @class = 'chapter']",
'chapter_mark': u'pagebreak',
'comments': None,
'cover': u'C:\\Users\\Kevin\\AppData\\Local\\Temp\\calibre_ ynk6si\\xcm0kg.jpeg',
'custom_size': u'6.8 x 9.5',
'debug_pipeline': None,
'dehyphenate': True,
'delete_blank_paragraphs': True,
'disable_font_rescaling': True,
'duplicate_links_in_toc': False,
'embed_all_fonts': True,
'embed_font_family': None,
'enable_heuristics': False,
'expand_css': True,
'extra_css': None,
'filter_css': u'',
'fix_indents': True,
'font_size_mapping': None,
'format_scene_breaks': True,
'html_unwrap_factor': 0.4,
'input_encoding': None,
'input_profile': <calibre.customize.profiles.KindleInput object at 0x00000207279F8710>,
'insert_blank_line': False,
'insert_blank_line_size': 0.5,
'insert_metadata': False,
'isbn': None,
'italicize_common_cases': True,
'keep_ligatures': True,
'language': None,
'level1_toc': None,
'level2_toc': None,
'level3_toc': None,
'line_height': 0.0,
'linearize_tables': False,
'margin_bottom': -1.0,
'margin_left': -1.0,
'margin_right': -1.0,
'margin_top': -1.0,
'markup_chapter_headings': True,
'max_toc_links': 0,
'minimum_line_height': 0.0,
'no_chapters_in_toc': True,
'no_inline_navbars': False,
'output_profile': <calibre.customize.profiles.TabletOutput object at 0x0000020727A10048>,
'page_breaks_before': u"//*[name()='h1' or name()='h2']",
'paper_size': u'letter',
'pdf_add_toc': False,
'pdf_default_font_size': 16,
'pdf_footer_template': None,
'pdf_header_template': None,
'pdf_mark_links': False,
'pdf_mono_family': u'Liberation Mono',
'pdf_mono_font_size': 16,
'pdf_page_margin_bottom': 72.0,
'pdf_page_margin_left': 72.0,
'pdf_page_margin_right': 72.0,
'pdf_page_margin_top': 72.0,
'pdf_page_numbers': False,
'pdf_sans_family': u'Liberation Mono',
'pdf_serif_family': u'Liberation Serif',
'pdf_standard_font': u'serif',
'prefer_metadata_cover': False,
'preserve_cover_aspect_ratio': False,
'pretty_print': False,
'pubdate': None,
'publisher': None,
'rating': None,
'read_metadata_from_opf': u'C:\\Users\\Kevin\\AppData\\Local\\Temp\\calibre_ ynk6si\\l4en4t.opf',
'remove_fake_margins': False,
'remove_first_image': False,
'remove_paragraph_spacing': False,
'remove_paragraph_spacing_indent_size': 1.5,
'renumber_headings': True,
'replace_scene_breaks': u'',
'search_replace': '[]',
'series': None,
'series_index': None,
'smarten_punctuation': False,
'sr1_replace': None,
'sr1_search': None,
'sr2_replace': None,
'sr2_search': None,
'sr3_replace': None,
'sr3_search': None,
'start_reading_at': None,
'subset_embedded_fonts': False,
'tags': None,
'timestamp': None,
'title': None,
'title_sort': None,
'toc_filter': None,
'toc_threshold': 6,
'toc_title': None,
'transform_css_rules': '[]',
'uncompressed_pdf': False,
'unit': u'inch',
'unsmarten_punctuation': False,
'unwrap_lines': True,
'use_auto_toc': False,
'use_profile_size': False,
'verbose': 2}
InputFormatPlugin: MOBI Input running
on C:\Users\Kevin\AppData\Local\Temp\calibre_ynk6si\w xqyzr.azw3
Found KF8 MOBI of type 'standalone'
Extracting text...
Parsing all content...
Parsing text/part0014.html ...
Parsing text/part0008.html ...
Parsing text/part0026.html ...
Parsing text/part0003.html ...
Parsing text/part0004.html ...
Parsing text/part0015.html ...
Parsing text/part0009.html ...
Parsing text/part0025.html ...
Parsing text/part0020.html ...
Parsing text/part0016.html ...
Parsing text/part0010.html ...
Parsing text/part0024.html ...
Parsing text/part0002.html ...
Parsing text/part0017.html ...
Parsing text/part0011.html ...
Parsing text/part0005.html ...
Parsing text/part0021.html ...
Parsing text/part0023.html ...
Parsing text/part0018.html ...
Parsing text/part0012.html ...
Parsing text/part0006.html ...
Parsing text/part0022.html ...
Parsing text/part0019.html ...
Parsing text/part0013.html ...
Parsing text/part0007.html ...
Parsing styles/0001.css ...
Parsing text/part0001.html ...
Parsing text/part0000.html ...
Reading TOC from NCX...
Merging user specified metadata...
Detecting structure...
Detected chapter: PART ONE:
Detected chapter: PART TWO:
Detected chapter: PART THREE:
Detected chapter: PART FOUR:
Flattening CSS and remapping font sizes...
Source base font size is 16.00000pt
Embedding font Arial Bold from c:\windows\fonts\arialbd.ttf
Python function terminated unexpectedly
'Item' object has no attribute 'xpath' (Error Code: 1)
Traceback (most recent call last):
File "site.py", line 101, in main
File "site.py", line 78, in run_entry_point
File "site-packages\calibre\utils\ipc\worker.py", line 195, in main
File "site-packages\calibre\gui2\convert\gui_conversion.py", line 33, in gui_convert_override
File "site-packages\calibre\gui2\convert\gui_conversion.py", line 26, in gui_convert
File "site-packages\calibre\ebooks\conversion\plumber.py", line 1222, in run
File "site-packages\calibre\ebooks\oeb\transforms\embed_fonts .py", line 114, in __call__
File "site-packages\calibre\ebooks\oeb\transforms\embed_fonts .py", line 182, in process_item
File "site-packages\calibre\ebooks\oeb\transforms\embed_fonts .py", line 187, in find_usage_in
File "site-packages\calibre\ebooks\oeb\transforms\embed_fonts .py", line 187, in find_usage_in
File "site-packages\calibre\ebooks\oeb\transforms\embed_fonts .py", line 195, in find_usage_in
File "site-packages\calibre\ebooks\oeb\transforms\embed_fonts .py", line 247, in embed_font
File "site-packages\calibre\ebooks\oeb\transforms\embed_fonts .py", line 236, in do_embed
File "site-packages\calibre\ebooks\oeb\transforms\embed_fonts .py", line 159, in get_page_sheet
AttributeError: 'Item' object has no attribute 'xpath'