<human>:  how to tell if a string contains something.
<bot>: Here is a Python program to tell if a string contains something

import pandas as pd

def contains(s, sub):
  """Check if a string contains a substring."""
  return s.find(sub)!= -1

# Enter the string
s = "This is a string"

# Calling the function
print((contains(s, "is")))

#Example Output
# True

#Remember to inspect code for bugs.