PdfMiner: Erro processing the page literal required: /b'begin' - python-3.x

Question

I am trying to read .pdf file using python3 with package called pdfminer which I have done successfully but for some of the page in .pdf file while reading the page using interpreter.process_page in getAllPages() of the following code I am getting an errors as follows:
error processing the page literal required: /b'begin'.
error processing the page Unknown operator: 'Qq'.
This is happening only for few docs but not able to find out what is the problem , in which case this could happen?
Code:-
class PDFDoc():
def __init__(self):
self.rsrcmgr = PDFResourceManager()
self.laparams = LAParams()
self.device = PDFPageDetailedAggregator(self.rsrcmgr, laparams=self.laparams)
self.interpreter = PDFPageInterpreter(self.rsrcmgr, self.device)
self.doc_values = []
self.total_no_of_pages = 0
self.doc_page_dict = collections.OrderedDict()
# self.doc = None
"""
Read PDF Document
"""
def readDoc(self, doc_name):
fp = open(doc_name, 'rb')
self.parser = PDFParser(fp)
self.doc = PDFDocument(self.parser)
"""
Read all pages in the document and saved in List of tuples format.
It contains the text and their coordinate info along with page number
"""
def getAllPages(self):
for page in PDFPage.create_pages(self.doc):
self.interpreter.process_page(page)
# receive the LTPage object for this page
self.device.get_result()
self.doc_values = self.device.rows
"""
Get the total number of pages
"""
def getTotalPages(self):
self.total_no_of_pages = max(self.doc_page_dict)+1
"""
Convert the document info into Page-wise dict. {Key:Value}-->{Page no:[Page text, coordinates]}
"""
def getPageDict(self):
for i in range(len(self.doc_values)):
left = self.doc_values[i][1]
bottom = self.doc_values[i][2]
content = self.doc_values[i][-1]
if self.doc_page_dict.get(self.doc_values[i][0]):
self.doc_page_dict[self.doc_values[i][0]].append({'left':left, 'bottom':bottom, 'content':content})
else:
self.doc_page_dict[self.doc_values[i][0]]=[{'left':left, 'bottom':bottom, 'content':content}]
"""
Align the page text in case they are misaligned
"""
def create_page_table_modified(self, pagedict_list):
# ##print(pagedict_list)
page_dict = collections.OrderedDict()
page_table_1 = []
page_table = []
exc_arr = []
count = 0
for line in pagedict_list:
row = []
temp_key = float(line['bottom'])
if not line in exc_arr and line["content"]:
row.append(line)
exc_arr.append(line)
for line_1 in pagedict_list:
if not line_1 in exc_arr and line_1["content"]:
# #print('last_top:', last_top, each_dict_adjusted['bottom'])
if abs(int(line["bottom"]) - int(line_1["bottom"])) <= 6:
row.append(line_1)
exc_arr.append(line_1)
if row:
page_dict[temp_key] = row
page_table.append(row)
count += 1
# ##print("\n\nPage:",page_table)
page_dict_keys = sorted(page_dict, reverse=True)
for i in page_dict_keys:
# i = sorted(i, key=lambda k: k['left'])
page_table_1.append(page_dict[i])
return page_table_1
"""
Sort the line elements based on its position coordinates
"""
def sortRowElements(self,row_list):
return sorted(row_list, key=lambda k:k['left'])
"""
Combine line elements to form the line text
"""
def combineText(self, row):
temp_ = []
# for i in range(len(row)):
text = [k['content'] for k in row]
temp_.append(' '.join(text))
return ' '.join(temp_)
"""
To call aligning and sorting functions
"""
def sortText(self):
for page in self.doc_page_dict:
self.doc_page_dict[page] = self.create_page_table_modified(self.doc_page_dict[page])
self.doc_page_dict[page] = [self.sortRowElements(line) for line in self.doc_page_dict[page]]
"""
To get text from particular page of the document --> List of line text
"""
def pageText(self, page_no):
page_text = [self.combineText(line) for line in self.doc_page_dict[page_no]]
return page_text
read_document = PDFDoc()