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Given the following text description, write Python code to implement the functionality described.
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Description:
Given a list of positive integers x. return a sorted list of all 
    elements that hasn't any even digit.
    Note: Returned list should be sorted in increasing order.
    
    For example:
    
This is how the function will work:
 unique_digits([15, 33, 1422, 1])
    [1, 15, 33]
    
This is how the function will work:
 unique_digits([152, 323, 1422, 10])
    []
    
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Python Code:
def unique_digits(x):
    
    odd_digit_elements = []
    for i in x:
        if all (int(c) % 2 == 1 for c in str(i)):
            odd_digit_elements.append(i)
    return sorted(odd_digit_elements)
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