sample Python code using SQS

reader.py

import boto3

sqs = boto3.client('sqs', region_name="us-west-2",
            aws_access_key_id='',
            aws_secret_access_key=''
        )
queue_url = ''


response = sqs.receive_message(
    QueueUrl=queue_url,
    AttributeNames=[
        'SentTimestamp'
    ],
    MaxNumberOfMessages=1,
    MessageAttributeNames=[
        'All'
    ],
    VisibilityTimeout=0,
    WaitTimeSeconds=0
)

message = response['Messages'][0]
receipt_handle = message['ReceiptHandle']

sqs.delete_message(
    QueueUrl=queue_url,
    ReceiptHandle=receipt_handle
)
print('Received and deleted message: %s' % message)

writer.py

import boto3

sqs = boto3.client('sqs', region_name="us-west-2",
            aws_access_key_id='',
            aws_secret_access_key=''
        )
queue_url = ''


response = sqs.send_message(
    QueueUrl=queue_url,
    DelaySeconds=10,
    MessageAttributes={
        'Title': {
            'DataType': 'String',
            'StringValue': 'The Whistler'
        },
        'Author': {
            'DataType': 'String',
            'StringValue': 'John Grisham'
        },
        'WeeksOn': {
            'DataType': 'Number',
            'StringValue': '6'
        }
    },
    MessageBody=(
        'Information about current NY Times fiction bestseller for '
        'week of 12/11/2016.'
    )
)

print(response['MessageId'])

I think the issue is with the MessageBody statement. You have 2 separate strings without a comma separator. Either combine the 2 strings into 1 longer string or try adding a comma between the 2 strings.