<｜begin▁of▁sentence｜>### Instruction:
As a cryptographer, you may need to develop algorithms and protocols for secure communication and data encryption, such as using the igraph module to manage configurations. Suppose you are working on a project involving network analysis using the NetworkX library. In this context, you have to use the NetworkX Configuration class to handle configurations, specifically to check if the 'verbose' key exists, set its value, and save the configuration to a file.
### Response:
from igraph import Configuration

# Accessing the singleton configuration instance
config = Configuration.instance()

# Set the verbose configuration to True
config['verbose'] = True

# Check if 'verbose' key exists in the configuration
verbose_exists = 'verbose' in config
print('Verbose exists:', verbose_exists)

# Get the current value of 'verbose'
verbose_value = config['verbose']
print('Verbose value:', verbose_value)

# Save the current configuration to a file
with open('igraph_config.txt', 'w') as f:
    config.save(f)

# Load the configuration from a file
with open('igraph_config.txt', 'r') as f:
    config.load(f)
<|EOT|>
