def str_is_pos_int(numeric_string):
    """Returns true if the string is a positive integer
    
    Arguments
    ---------
    string : str
        String representing a number
    
    Returns
    -------
    bool
        True if the string is a positive integer
    """
    is_int = False
    if numeric_string:
        if numeric_string.isdigit():
            is_int = True
    return is_int
