#!/usr/bin/env python
def convert(inp):
    """
    * Get the input from user.
    * Parse the input to extract numbers
    ** Split by comma
    *** Each item in the list will then be split by '-'
    **** Populate the number between a-b using range(a,b)
    >>> convert("")
    []
    >>> convert("1")
    [1]
    >>> convert("1,2")
    [1, 2]
    >>> convert("1,2-5")
    [1, 2, 3, 4, 5]
    >>> convert("1-3,2-5,8,10,15-20")
    [1, 2, 3, 2, 3, 4, 5, 8, 10, 15, 16, 17, 18, 19, 20]
    """
    if not inp:  # empty string must return an empty list
        return []
    pages = []
    comma_separated = []
    comma_separated = inp.split(",")     # split the input string based on comma delimitation
    for item in comma_separated:
        if "-" in item:
            a = item.split("-")
            pages.extend(range(int(a[0]),int(a[1])+1))
        else:
            pages.append(int(item))
    return pages
if __name__ == '__main__' :
    import doctest
    doctest.testmod()