Upgrade V11 to V12 Migration error on panda

Hello
I am upgrading V11 to V12. I having challenges on migration step.

Success: Done in 0.022s
Updating DocTypes for frappe : [== ]
Traceback (most recent call last):
File “/usr/local/lib/python3.6/runpy.py”, line 193, in _run_module_as_main
main”, mod_spec)
File “/usr/local/lib/python3.6/runpy.py”, line 85, in _run_code
exec(code, run_globals)
File “/home/frappe/frappe-bench/apps/frappe/frappe/utils/bench_helper.py”, line 97, in
main()
File “/home/frappe/frappe-bench/apps/frappe/frappe/utils/bench_helper.py”, line 18, in main
click.Group(commands=commands)(prog_name=‘bench’)
File “/home/frappe/frappe-bench/env/lib/python3.6/site-packages/click/core.py”, line 764, in call
return self.main(*args, **kwargs)
File “/home/frappe/frappe-bench/env/lib/python3.6/site-packages/click/core.py”, line 717, in main
rv = self.invoke(ctx)
File “/home/frappe/frappe-bench/env/lib/python3.6/site-packages/click/core.py”, line 1137, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File “/home/frappe/frappe-bench/env/lib/python3.6/site-packages/click/core.py”, line 1137, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File “/home/frappe/frappe-bench/env/lib/python3.6/site-packages/click/core.py”, line 956, in invoke
return ctx.invoke(self.callback, **ctx.params)
File “/home/frappe/frappe-bench/env/lib/python3.6/site-packages/click/core.py”, line 555, in invoke
return callback(*args, **kwargs)
File “/home/frappe/frappe-bench/env/lib/python3.6/site-packages/click/decorators.py”, line 17, in new_func
return f(get_current_context(), *args, **kwargs)
File “/home/frappe/frappe-bench/apps/frappe/frappe/commands/init.py”, line 25, in _func
ret = f(frappe._dict(ctx.obj), *args, **kwargs)
File “/home/frappe/frappe-bench/apps/frappe/frappe/commands/site.py”, line 233, in migrate
migrate(context.verbose, rebuild_website=rebuild_website, skip_failing=skip_failing)
File “/home/frappe/frappe-bench/apps/frappe/frappe/migrate.py”, line 50, in migrate
frappe.model.sync.sync_all(verbose=verbose)
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/sync.py”, line 19, in sync_all
sync_for(app, force, verbose=verbose, reset_permissions=reset_permissions)
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/sync.py”, line 56, in sync_for
reset_permissions=reset_permissions, for_sync=True)
File “/home/frappe/frappe-bench/apps/frappe/frappe/modules/import_file.py”, line 66, in import_file_by_path
ignore_version=ignore_version, reset_permissions=reset_permissions)
File “/home/frappe/frappe-bench/apps/frappe/frappe/modules/import_file.py”, line 141, in import_doc
doc.insert()
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 259, in insert
self.run_post_save_methods()
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 919, in run_post_save_methods
self.run_method(“on_update”)
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 787, in run_method
out = Document.hook(fn)(self, *args, **kwargs)
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 1058, in composer
return composed(self, method, *args, **kwargs)
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 1041, in runner
add_to_return_value(self, fn(self, *args, **kwargs))
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 781, in
fn = lambda self, *args, **kwargs: getattr(self, method)(*args, **kwargs)
File “/home/frappe/frappe-bench/apps/frappe/frappe/core/doctype/doctype/doctype.py”, line 299, in on_update
self.run_module_method(“on_doctype_update”)
File “/home/frappe/frappe-bench/apps/frappe/frappe/core/doctype/doctype/doctype.py”, line 368, in run_module_method
module = load_doctype_module(self.name, self.module)
File “/home/frappe/frappe-bench/apps/frappe/frappe/modules/utils.py”, line 204, in load_doctype_module
doctype_python_modules[key] = frappe.get_module(module_name)
File “/home/frappe/frappe-bench/apps/frappe/frappe/init.py”, line 814, in get_module
return importlib.import_module(modulename)
File “/home/frappe/frappe-bench/env/lib/python3.6/importlib/init.py”, line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File “”, line 994, in _gcd_import
File “”, line 971, in _find_and_load
File “”, line 955, in _find_and_load_unlocked
File “”, line 665, in _load_unlocked
File “”, line 678, in exec_module
File “”, line 219, in _call_with_frames_removed
File “/home/frappe/frappe-bench/apps/frappe/frappe/core/doctype/data_import_beta/data_import_beta.py”, line 8, in
from frappe.core.doctype.data_import.importer_new import Importer
File “/home/frappe/frappe-bench/apps/frappe/frappe/core/doctype/data_import/importer_new.py”, line 14, in
from frappe.utils.xlsxutils import (
File “/home/frappe/frappe-bench/apps/frappe/frappe/utils/xlsxutils.py”, line 7, in
import openpyxl
File “/home/frappe/frappe-bench/env/lib/python3.6/site-packages/openpyxl/init.py”, line 6, in
from openpyxl.workbook import Workbook
File “/home/frappe/frappe-bench/env/lib/python3.6/site-packages/openpyxl/workbook/init.py”, line 4, in
from .workbook import Workbook
File “/home/frappe/frappe-bench/env/lib/python3.6/site-packages/openpyxl/workbook/workbook.py”, line 7, in
from openpyxl.worksheet.worksheet import Worksheet
File “/home/frappe/frappe-bench/env/lib/python3.6/site-packages/openpyxl/worksheet/worksheet.py”, line 24, in
from openpyxl.cell import Cell, MergedCell
File “/home/frappe/frappe-bench/env/lib/python3.6/site-packages/openpyxl/cell/init.py”, line 3, in
from .cell import Cell, WriteOnlyCell, MergedCell
File “/home/frappe/frappe-bench/env/lib/python3.6/site-packages/openpyxl/cell/cell.py”, line 41, in
from pandas import Timestamp
File “/home/frappe/frappe-bench/env/lib/python3.6/site-packages/pandas/init.py”, line 54, in
from pandas.core.api import (
File “/home/frappe/frappe-bench/env/lib/python3.6/site-packages/pandas/core/api.py”, line 29, in
from pandas.core.groupby import Grouper, NamedAgg
File “/home/frappe/frappe-bench/env/lib/python3.6/site-packages/pandas/core/groupby/init.py”, line 1, in
from pandas.core.groupby.generic import DataFrameGroupBy, NamedAgg, SeriesGroupBy
File “/home/frappe/frappe-bench/env/lib/python3.6/site-packages/pandas/core/groupby/generic.py”, line 56, in
import pandas.core.algorithms as algorithms
AttributeError: module ‘pandas’ has no attribute ‘core’

A web search points to these clues - to install another pandas version, a locale setting, your xlsx spreadsheet import is expected encoding and so on python - Importing Pandas gives error AttributeError: module 'pandas' has no attribute 'core' in iPython Notebook - Stack Overflow