Write a function to count the number of sublists containing a particular element.
def count_element_in_list(list1, x): 
    ctr = 0
    for i in range(len(list1)): 
        if x in list1[i]: 
            ctr+= 1          
    return ctr
<s>[INST]<<SYS>>Given a task and its code, generate test cases for the code.<</SYS>>Write a function to count the number of sublists containing a particular element.
def count_element_in_list(list1, x): 
    ctr = 0
    for i in range(len(list1)): 
        if x in list1[i]: 
            ctr+= 1          
    return ctr[/INST]assert count_element_in_list([[1, 3], [5, 7], [1, 11], [1, 15, 7]],1)==3
assert count_element_in_list([['A', 'B'], ['A', 'C'], ['A', 'D', 'E'], ['B', 'C', 'D']],'A')==3
assert count_element_in_list([['A', 'B'], ['A', 'C'], ['A', 'D', 'E'], ['B', 'C', 'D']],'E')==1</s>