Pdf printing error in quatation

dear team,

please solve my error in the pdf.

Server Error
Traceback (most recent call last):
File “/opt/bitnami/apps/erpnext/htdocs/frappe-bench/env/lib/python3.7/site-packages/pdfkit/configuration.py”, line 21, in init
with open(self.wkhtmltopdf) as f:
FileNotFoundError: [Errno 2] No such file or directory: b’’

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File “/opt/bitnami/apps/erpnext/htdocs/frappe-bench/apps/frappe/frappe/app.py”, line 62, in application
response = frappe.api.handle()
File “/opt/bitnami/apps/erpnext/htdocs/frappe-bench/apps/frappe/frappe/api.py”, line 56, in handle
return frappe.handler.handle()
File “/opt/bitnami/apps/erpnext/htdocs/frappe-bench/apps/frappe/frappe/handler.py”, line 22, in handle
data = execute_cmd(cmd)
File “/opt/bitnami/apps/erpnext/htdocs/frappe-bench/apps/frappe/frappe/handler.py”, line 61, in execute_cmd
return frappe.call(method, **frappe.form_dict)
File “/opt/bitnami/apps/erpnext/htdocs/frappe-bench/apps/frappe/frappe/init.py”, line 1055, in call
return fn(*args, **newargs)
File “/opt/bitnami/apps/erpnext/htdocs/frappe-bench/apps/frappe/frappe/utils/print_format.py”, line 92, in download_pdf
frappe.local.response.filecontent = get_pdf(html)
File “/opt/bitnami/apps/erpnext/htdocs/frappe-bench/apps/frappe/frappe/utils/pdf.py”, line 38, in get_pdf
filedata = pdfkit.from_string(html, False, options=options or {})
File “/opt/bitnami/apps/erpnext/htdocs/frappe-bench/env/lib/python3.7/site-packages/pdfkit/api.py”, line 70, in from_string
configuration=configuration, cover_first=cover_first)
File “/opt/bitnami/apps/erpnext/htdocs/frappe-bench/env/lib/python3.7/site-packages/pdfkit/pdfkit.py”, line 42, in init
self.configuration = (Configuration() if configuration is None
File “/opt/bitnami/apps/erpnext/htdocs/frappe-bench/env/lib/python3.7/site-packages/pdfkit/configuration.py”, line 27, in init
https://github.com/JazzCore/python-pdfkit/wiki/Installing-wkhtmltopdf’ % self.wkhtmltopdf)
OSError: No wkhtmltopdf executable found: “b’’”
If this file exists please check that this process can read it. Otherwise please install wkhtmltopdf - https://github.com/JazzCore/python-pdfkit/wiki/Installing-wkhtmltopdf