Human: determine if data frame has a null. Assistant: 
Here is a Python program to determine if a data frame has a null value

import pandas as pd

def isnull(df):
    """
    Returns True if data frame has a null

    :param df:
    :return:
    """

    return df.isnull().any()

# Enter the data frame
df = pd.DataFrame({"a": [1, 2, 3, 4, 5, 6, 7, 8, 9, 10],
                   "b": [1, 2, 3, 4, 5, 6, 7, 8, 9, 10],
                   "c": [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]})

# Calling the function
print((isnull(df)))

#Example Output
# a    False
# b    False
# c    False
# dtype: bool

#Remember to inspect code for bugs.