<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def prange(N=1, dim=1):
 """ Constructor to create a range of polynomials where the exponent vary. Args: N (int):
 Number of polynomials in the array. dim (int):
 The dimension the polynomial should span. Returns: (Poly):
 A polynomial array of length N containing simple polynomials with increasing exponent. Examples: [1, q0, q0^2, q0^3] [1, q2, q2^2, q2^3] """

    A = {}
    r = numpy.arange(N, dtype=int)
    key = numpy.zeros(dim, dtype=int)
    for i in range(N):
        key[-1] = i
        A[tuple(key)] = 1*(r==i)

    return Poly(A, dim, (N,), int)